The Betting Angle
Karen Khachanov has already survived one of the most physically demanding matches of the US Open. Alexander Blockx has produced one of the tournament’s biggest breakthrough runs.
That combination makes this quarterfinal much more complicated than a simple favorite-versus-underdog matchup.
Khachanov enters as the market favorite after defeating Learner Tien in five sets, while Blockx reached his first Grand Slam quarterfinal by beating Flavio Cobolli and Francisco Cerundolo. The bigger betting question is whether Blockx can physically recover after revealing that a rib problem nearly forced him to retire against Cerundolo.
Reader Betting Snapshot
Game: Karen Khachanov vs. Alexander Blockx
Date: September 9, 2026
Venue: Arthur Ashe Stadium
Best Bet: Khachanov Moneyline
Current Market: approximately -170 to -180
Confidence: ★★★★☆
Risk Level: Moderate
$100 Profit: approximately $56–$59
Best Time to Bet: Compare prices before match time; avoid paying above the current market range
One current sportsbook lists Khachanov at 11/20 (-182) and Blockx at 11/8 (+138), while another market currently has Khachanov around -170. Totals are sitting around 39.5–40.5 games.
Why This Match Is Different
Khachanov has the résumé.
Blockx has the momentum.
The Belgian is the youngest player remaining in the men’s draw and has climbed dramatically during 2026. The official US Open site notes that he entered the year outside the Top 100 and has risen to a live ranking around No. 26 after reaching the Madrid Masters semifinals and now the US Open quarterfinals.
Khachanov, meanwhile, arrived in New York after losing four consecutive matches, including three straight summer hard-court tune-ups.
That makes his turnaround particularly impressive.
He has now beaten Felix Auger-Aliassime and Learner Tien in the same tournament and is back in a Grand Slam quarterfinal for the seventh time.
The Number That Matters
The current moneyline tells us something important.
Books are pricing Khachanov as the better player, but they are not treating Blockx like an ordinary No. 28 seed.
That distinction matters.
At around -170, Khachanov needs to win roughly 63% of the time just to break even before accounting for the bookmaker margin. At -200, that requirement jumps to 66.7%.
That is a meaningful difference.
For that reason, the moneyline becomes much less attractive if the market pushes Khachanov substantially higher.
The Physical Question
This is where the matchup gets interesting.
Khachanov spent 3 hours and 49 minutes battling Tien in a five-set match. He won 7-5, 4-6, 6-7(6), 6-1, 6-4.
Blockx also went four sets against Cerundolo, but his concern is different.
He said he came close to retiring because of a rib issue during the match. The Belgian still managed to close out a 6-3, 4-6, 7-5, 7-5 victory.
That creates two separate physical questions rather than one.
Khachanov has the heavier workload.
Blockx has the more obvious injury uncertainty.
The Matchup
Khachanov’s path should be straightforward: use his serve and weight of shot to prevent Blockx from dictating long stretches from the baseline.
Blockx’s best route is to take more initiative.
Khachanov himself described the Belgian as having a big serve and a steady baseline game, while noting that Blockx takes more risks with his forehand.
That could produce a match with relatively short momentum swings.
If Blockx serves efficiently, his aggressive forehand can prevent Khachanov from establishing consistent pressure.
If Khachanov gets repeated looks at second serves, however, his experience in these stages of Grand Slams becomes a major advantage.
Hidden Betting Edge
Don’t Ignore the Recovery Timeline
The casual betting angle is simply “Khachanov is experienced.”
The sharper angle is which player has the greater physical uncertainty?
Khachanov’s fatigue is measurable.
Blockx’s rib problem is less predictable.
That makes the favorite’s moneyline preferable to a Khachanov handicap. A straight-set or dominant Khachanov win requires him to control the match from beginning to end. The moneyline only requires him to survive the matchup.
What Could Go Wrong
The biggest danger is Khachanov’s legs.
If his five-set battle with Tien affects his serve or movement, Blockx has enough firepower to capitalize.
The other risk is Blockx’s physical condition. If the rib problem is still limiting his rotation or serve, the match could move sharply toward Khachanov.
Bets We’re Avoiding
Khachanov -2.5 games at an inflated price.
The handicap can win, but the physical uncertainty makes the moneyline cleaner.
Best Bet
Karen Khachanov Moneyline — Target -170 or better
Confidence: ★★★★☆
Risk: Moderate
Khachanov has the Grand Slam experience, the hard-court pedigree and the momentum of a major upset over Tien. Blockx is dangerous, but his physical situation introduces another layer of uncertainty.
The best approach is to back Khachanov without demanding a dominant victory.
Check the latest tennis markets and compare the price before locking in your wager: https://tinyurl.com/2hkk2pvm
Alternative Betting Option
Over 39.5 games is worth consideration around even-money territory. Current markets show totals between 39.5 and 40.5, and one sportsbook currently prices Over 39.5 at 10/11.
Sports Betting Ace’s Final Prediction: Khachanov wins 3-1.
Which side are you taking — the proven Grand Slam veteran or the Belgian breakout star?