The quarterfinals are finally here, and Day 9 at Flushing Meadows is absolutely loaded. Four blockbuster matchups. One electric atmosphere. And a betting slate that has sharp bettors circling like sharks. Rain delayed the start to 1:00 PM ET, but that just bought us extra time to break down every angle, every mismatch, and every spot where the books might have slipped up. We're talking revenge narratives, statistical nightmares, and a clear route to a monster accumulator that could make your Monday unforgettable. Here's exactly where the value sits for your US Open tennis day nine predictions, acca tips and odds.
The "Safe" Leg: Sinner to Dominate Medvedev Again
If you're building an acca today, the anchor has to be Jannik Sinner to cover the -6.5 game handicap at -110 (1.91). This isn't just a pick - it's a statistical mismatch that jumps off the page. Sinner leads the head-to-head 8-4, and crucially, he's won their last five hard-court meetings. That includes a straight-sets demolition in the 2026 Australian Open final that had Medvedev shaking his head in disbelief. The World No. 1's ability to redirect Medvedev's defensive rallies into outright winners is the single biggest mismatch we've seen in this tournament.
📊 Sinner has won 8 of 12 career meetings vs. Medvedev - including five straight on hard courts dating back to 2024.
Medvedev's deep-return positioning and counterpunching style is tailor-made for Sinner's raw power and clean ball-striking. The Italian hits through the court with such pace that even Medvedev's rubber-band defense stretches to its breaking point. Sure, the night session should bring slightly cooler conditions - but Sinner's proven ability to break down the Medvedev serve is what gives us real confidence. He's converted 34% of his break chances against the Russian in their last five meetings. That spells straight sets, and the -6.5 handicap covered with room to spare.
Table: Sinner vs. Medvedev - Key Hard Court Numbers
| Metric | Sinner | Medvedev |
|---|---|---|
| H2H Wins (Hard) | 5 | 0 |
| 2026 Hard Court Win % | 92% | 78% |
| Break Points Converted (H2H) | 34% | 21% |
| Average Games Lost/Set (QF) | 3.1 | 4.8 |
Add Sinner to your acca as the foundational leg, then shift your focus to the women's side for the next piece of the puzzle. The value is real. The form is undeniable. And the matchup is an absolute nightmare for Medvedev supporters.
Layup or Trap? Gauff and Alcaraz in Action
Gauff's Serve vs. Zheng's Return
Coco Gauff (-260) is expected to handle Qinwen Zheng (+210) in the second match on Arthur Ashe, and the market is all over the American sensation. Sharp money is flooding in on Gauff covering the -4.5 game spread (-120) , and her home-crowd advantage at Flushing Meadows is worth at least a couple of games on its own. But here's the wrinkle - and you absolutely need to know this before locking it into your parlay.
📊 Zheng's first-serve win rate is 88% this fortnight - the highest of any remaining woman in the draw.
That number jumps off the screen. Zheng has served like a woman possessed through her first four matches. Gauff's break-point save rate (56%) is solid but hardly spectacular. If Zheng holds serve consistently and keeps the sets tight, this could get far closer than the odds suggest. We still love Gauff to win - she leads the head-to-head 4-1 and has the returning prowess to eventually solve Zheng's delivery. But we're far more confident in the Sinner handicap. Use Gauff to win outright in your acca. Consider the -4.5 games only if you want extra juice and can stomach a potential sweat.
Alcaraz: The Heavyweight Lock
There isn't much mystery here. Carlos Alcaraz (-600) versus Stefanos Tsitsipas (+450) is the most lopsided match of the day - and the odds reflect that reality perfectly. Alcaraz has won six of seven career meetings. Tsitsipas' one-handed backhand remains a glaring vulnerability against Alcaraz's high-kicking forehand that consistently pushes the Greek out of his comfort zone.
