Aryna Sabalenka and Elena Rybakina both won their Thursday night semifinals to set up Saturday's US Open final, and Polymarket's title contracts moved hard doing it. Sabalenka beat Jessica Pegula 7-5, 6-2 and her "Will Aryna Sabalenka win the 2026 Women's US Open?" contract jumped from 35.5c to a 60.5c intraday high, settling 55.5c. Rybakina dropped the first set to Coco Gauff, saw her own contract fall to a 12.05c intraday low, then completed a 3-6, 6-4, 6-4 comeback that carried it back up to a 44.65c high, settling 42.75-42.85c. Numbers below are from Gamma and the CLOB, fetched 2026-09-11 11:35 UTC.
01The semifinalsA routine win and a three-set escape
Sabalenka's path to a fourth straight US Open final was the calmer of the two. She closed out the first set 7-5 against Pegula, then the second was one-sided at 6-2 - a result that extends her winning streak at the tournament to 19 matches and leaves her one win from a third consecutive US Open title. Polymarket's book reflected the lopsided scoreline: her contract barely moved through the first set, then climbed in a series of steps once she began pulling away, from 35.5c before the match to a 60.5c peak shortly after the final point, before giving back a few points to settle near 55.5c against Rybakina in the final.
Rybakina's night went the other way first. Gauff took the opening set 6-3 in 38 minutes, and Rybakina's contract slid to a 12.05c low - roughly a fifth of where it had opened the day - before Gauff's early 4-1 lead in the second set evaporated as Rybakina drew level at 4-4 and closed it out. A tight third set, level at 3-3, tipped Rybakina's way for the final two games. The contract's shape mirrors the match: a crater during the first set, a fast climb through the second and third as the momentum swung, and a settle near 42.75c once Gauff's contract was marked resolved to 0 at 2026-09-11 06:10 UTC.
02The chartOne contract climbs in steps, the other in a V
The two lines tell different stories about how a match gets priced. Sabalenka's climbs in discrete steps as the scoreline confirms itself - each game she won against Pegula nudged the contract up, with no sharp single jump because the outcome was rarely in doubt. Rybakina's is a single deep V: a fast fall as she lost the first set, a long stretch of uncertainty through most of the second, then one steep climb once she broke serve for the match in the third. Both lines flatten out once the locker-room reporting confirmed the results and the market had nothing left to react to before Saturday.
03What's leftA rubber match, and a thinner book on the challenger
2026 WOMEN'S US OPEN YES 24H
Sabalenka 55.5c +18.5c
Rybakina 42.75c +16.8c
Sabalenka and Rybakina have split their two prior Grand Slam finals - Sabalenka won the 2023 Australian Open, Rybakina won the 2026 Australian Open - and lead the head-to-head 10-7 overall, so Saturday's US Open final is a rubber match between the sport's two most dominant hard-court players this season. Sabalenka is chasing a third consecutive US Open title and has not lost a match at Flushing Meadows since 2023. The order books show the market treats her as the clearer favorite in more than just price: her contract has a 1c-wide market (3,968 shares bid at 55c, 2,790 offered at 56c), while Rybakina's book is both wider (a 2.4c spread, 41.6c bid against 44c ask) and thinner at the touch, with only 100 shares resting on the best bid. The final is scheduled for Saturday, September 12 at 4pm ET (20:00 UTC) on Arthur Ashe Stadium, the last placement left on the women's ladder.
04Following it liveWatching a final-day repricing as it happens
A two-name market like this one goes quiet for most of a day, then reprices point by point once the match starts - the way Rybakina's contract fell to 12c and climbed back to 43c inside three hours Thursday night. polymarket-tui shows a market's order book and price chart on one screen, so a swing like that shows up as a live moving line rather than something you find out about after the fact by reloading a page.
$ uv tool install polymarket-tui
$ polymarket-tui
No account is needed to browse markets, books, and charts. The install page has Homebrew and one-liner options.