--- title: "Esports First-Map Winners on Polymarket: 9,501 Best-of-Three Series in CS2, Valorant, Dota 2 and LoL" canonical: "https://0xinsider.com/research/esports-first-map-winner-polymarket" datePublished: "2026-09-14" dateModified: "2026-09-14" description: "The Map 1 or Game 1 winner went on to win 79.5% of 9,501 best-of-three esports series settled on Polymarket, against the 75% two evenly matched teams would give. 58.7% of series were swept 2-0. Favorites at the starting price came in close to fair." --- # Esports First-Map Winners on Polymarket: 9,501 Best-of-Three Series in CS2, Valorant, Dota 2 and LoL Last updated: 2026-09-14 Canonical: https://0xinsider.com/research/esports-first-map-winner-polymarket A Polymarket esports series settles on three markets that all have to agree: who won the series, who won each map, and how many maps were played. Checking 9,504 best-of-three series across CS2, Valorant, Dota 2 and League of Legends against each other, the three markets agreed on all but 3. On the 9,501 that checked out, the winner of Map 1 or Game 1 went on to win the series 79.5% of the time, above the 75% two evenly matched teams would produce, and 58.7% of series were swept 2-0, well above the 50% coin-flip baseline. The series favorite at the start, priced at an average of 68.0 cents, won 68.1% of the time, close enough to its price that betting every favorite lost 1.62% after Polymarket's taker fee. ## How we counted an esports series Polymarket lists a best-of-three esports series as a moneyline market, its title carrying "(BO3)": "Counter-Strike: Falcons Force vs mellren (BO3)". Three more markets sit on the same event: a "Map 1 Winner" market for CS2 and Valorant or a "Game 1 Winner" market for Dota 2 and LoL, a second one for map or game 2, and a "Games Total: O/U 2.5" market that pays Over if the series went to three games and Under if it was swept in two. Those three settlements do not have to agree; they are separate markets, sometimes resolved by different operators at different times. So before counting anything, we checked them against each other: a team that won both map or game 1 and map or game 2 must be the series winner, and winning both must mean the Games Total market settled Under 2.5. Any series that was not swept must have split the first two maps between the two teams. Of 9,504 series where all four markets settled, 3 disagree; they are listed below and left out. The rest, 9,501, is the sample this study uses. ## 9,501 series across four games The sample runs from November 4, 2025 to September 14, 2026: 4,954 CS2 series, 1,490 Dota 2, 1,532 LoL and 1,525 Valorant, every one a best-of-three moneyline that traded $100 or more with a settled series result, a settled first map or game, a settled second map or game, and a settled games-total market. Together they carried $1.82 billion in Polymarket's reported volume, out of $2.81 billion across every settled esports moneyline of any series length since January 2025. Left out: series without a title that names best-of-three, without a settled map or game 1, 2, or games-total market on the same event, and any moneyline that never traded. Best-of-one, best-of-five and best-of-seven series are not part of this study. ## The map 1 winner usually goes on to win the series Across the 9,501 counted series, the team that won Map 1 or Game 1 went on to win the series 79.5% of the time, with a half-width of 0.81 points. For two evenly matched teams, where each map is an independent coin flip, that number works out to 75%: win map 1, then either win map 2 outright or lose it and win the decider, 0.5 + 0.5 x 0.5. The measured rate sits a few points above that in every game: 79.8% in CS2, 78.6% in Dota 2, 81.1% in LoL and 77.7% in Valorant. That gap is what you would expect once real teams are not evenly matched: the stronger side in a mismatch is more likely to take map 1 and more likely to take the series, so the two events correlate more than a coin flip would. It is not evidence that winning a map somehow causes the series win beyond what team strength already explains. ## Sweeps happen far more than a coin flip would 58.7% of the 9,501 series were swept 2-0, against a 50% baseline for two evenly matched teams (the same team taking both maps, 0.5 x 0.5, doubled for either team). LoL swept most often, 62.0% of 1,532 series, CS2 and Valorant both sat near 58.2%, and Dota 2 swept 57.7% of the time. The sweep rate is the clearest sign that these are not even matches. A one-sided series ends in two games far more often than a close one does, so a sweep rate eight to twelve points above the coin-flip baseline says most best-of-three esports series have a clear favorite going in, which the next section prices directly. ## Checking three independent markets against each other 3 of 9,504 series, 0.03%, failed the cross-check. In two CS2 series, one team won both maps but the Games Total market settled Over 2.5 instead of Under, as if a third map had been played; in one Dota 2 series the two maps split but the Games Total market settled Under, as if the series had ended in two. All three read as a market resolved against the wrong outcome on one side of the check rather than a real three-game score with two winners, and none of the three is in the sample this study counts. That 99.97% agreement rate is itself a finding: on Polymarket, three independently settled esports markets on the same series describe the same match almost every time. It is also why this study can use the moneyline's own settlement for the series winner rather than reconstructing it from the map markets. ## The price already knows most of it 9,161 of the 9,501 series had a usable starting price: the last point in Polymarket's public price history at or before the series' listed start. The favorite, the side priced above 50 cents at that moment, averaged 68.0 cents and won 68.1% of the time, 0.08 points above its price, an interval that includes zero. The underdog, averaging 32.0 cents, won 31.9%. $1 on every favorite at its starting price returned minus 0.02% before fees and minus 1.62% after Polymarket's sports taker fee, an interval from minus 3.11% to minus 0.17% that sits under zero. $1 on every underdog returned minus 6.16% after the fee. Neither side beat its price by enough to matter; the fee, not a mispriced favorite or underdog, is what a flat bettor loses to. ## Favorites came in close to their price at every level Split by the favorite's starting price, no band strayed far from fair. Favorites priced 50¢ to 60¢, the largest band at 2,863 series, won 54.6%, 0.34 points below their price. The heaviest favorites, 90¢ and up on 492 series, won 95.7%, 2.23 points above their price, the one band whose interval clears zero (plus 0.39 to plus 3.95), and still returned plus 2.08% after the fee. By game, CS2 favorites came in almost exactly on price, 0.57 points, while Valorant favorites underperformed theirs by 2.77 points on 1,492 series, an interval from minus 5.07 to minus 0.42 that does not include zero. That is one game, one cut of the data; treat it as a lead to watch as the Valorant sample grows rather than a standing edge. ## The favorite does not always win Map 1 The pre-match favorite went on to win Map 1 or Game 1 itself 63.8% of the time, from 60.5% in Valorant to 68.2% in LoL. So in roughly one series in three, the underdog opens the series by taking the first map, and, per the headline rate above, still goes on to lose the series about four times in five. A first-map upset is a real signal but not a settled one. ## What this esports study does not show It covers best-of-three series only, in four games, and only series where a Map or Game 1, Map or Game 2 and Games Total market all existed and settled alongside the moneyline; best-of-one, best-of-five and best-of-seven formats are not part of it. It does not model roster changes, patches, LAN against online play, or which side of the map pool a team drew. The starting price is the last point in Polymarket's price history before the series' listed start, which can differ from the actual first-pull time by a few minutes on a delayed match; a buyer also pays the ask and, on a taker order, the fee modeled here. 340 series had no usable price and are not in the pricing tables, though they are in the win-rate and sweep-rate tables above. ## What it means for an esports bettor Winning Map 1 is meaningful, not decisive: about four series in five follow it, one in five does not. Sweeps are common in a real field of unevenly matched teams, so do not read a sweep as unusual once you have seen the price; 58.7% of series ending 2-0 is closer to what a field with real favorites produces than to a coin flip. The starting price is a fair estimate of who wins, at every level from 50 cents to 90-plus. The one gap that cleared zero, heavy favorites at 90¢ and up outperforming by 2.23 points, is worth a live-map check before laying a heavy chalk price, not a rule to bet blind. ## How to follow esports on 0xinsider The esports board at 0xinsider.com/sports/esports lists live and upcoming series with an active Polymarket market, with CS2, Valorant, League of Legends and Dota 2 each carrying their own board at 0xinsider.com/sports/esports/cs2, /valorant, /lol and /dota2. Every card shows both teams' prices, the price move over the last 24 hours, and the top holders on each side with their grades. Open a series for its event page, where the Markets section lists the moneyline beside the Map 1, Map 2 and Games Total markets and their volume. The whale alerts feed at 0xinsider.com/whale-alerts shows every large esports trade as it fills, and the guide at 0xinsider.com/learn/how-to-bet-on-esports-polymarket covers every market on a series and how each one settles. ## How to check the esports numbers yourself Every number on this page comes from three published runs: a read-only export of settled best-of-three moneylines and their map, game and totals markets at 16:10 UTC on September 14, 2026, a pull of each series' starting price from Polymarket's public CLOB API, and an analysis script that reproduces every table from those two files. All of them are at github.com/0xinsider/research, under polymarket-sports-markets, in the files whose names carry esports-map1. The universe is one settled best-of-three moneyline per CS2, Valorant, Dota 2 or LoL series that traded $100 or more, with a settled Map/Game 1, Map/Game 2 and Games Total market on the same event, agreeing across all four. Expect the count to grow with every series Polymarket lists. ## FAQ ### How often does the winner of Map 1 win the series in esports? 79.5% of the time, across 9,501 best-of-three CS2, Valorant, Dota 2 and LoL series settled on Polymarket, against a 75% baseline for two evenly matched teams. By game: 79.8% in CS2, 78.6% in Dota 2, 81.1% in LoL and 77.7% in Valorant. ### How often are esports series swept 2-0? 58.7% of 9,501 best-of-three series, well above the 50% two evenly matched teams would produce. LoL swept most often at 62.0%. ### Does the betting favorite usually win the first map? 63.8% of the time. In about one series in three the underdog takes Map 1 or Game 1, and still goes on to lose the series roughly four times in five. ### Is the esports moneyline price accurate at the start of a series? Close to it. Favorites, averaging 68.0 cents at the start, won 68.1% of 9,161 series, 0.08 points above their price with an interval that includes zero. $1 on every favorite lost 1.62% after Polymarket's taker fee, mostly the fee itself rather than a mispriced side. ### How reliable is Polymarket's esports settlement data? Very. Checking the series result against the Map/Game 1 winner, Map/Game 2 winner and Games Total markets on the same event, all three agreed on 9,501 of 9,504 series, 99.97%. The 3 that disagree are listed in the study and left out.