Grigor Dimitrov d Alexander Bublik 6-3 7-5
Dimitrov started off well against Agut last round, and was able to do the same against Bublik here, who can joke around. Dimitrov historically does better than most against taller opponents since people like Bublik have bigger split-step, meaning Dimitrov's late timing of hitting can wrong-foot opponents.
Pablo Carreno Busta (7) d Dominik Koepfer 6-4 6-2
Carreno-Busta continues his dominant form, although Koepfer did have his chances, converting 0/7 break point opportunities compared to 3/4 for PCB.
Felix Auger-Aliassime (12) d Karen Khachanov 6-7(5) 6-3 6-4
FAA dug deep, but he could have finished the match much quicker, with 3/13 break point opportunities compared to just 0/1 for FAA. FAA won 84% of his serves compared to just 61% for the Russian.
Guido Pella d Fabio Fognini 6-1 7-5
Pella can be relatively good at covering handicaps, as he remains mentally consistent, compared to Fognini, who never really makes it past a third round event. Consistency was all Pella really needed to get past Fognini, who only served at 55%, and converted 14% of break points.
Hubert Hurkacz (9) d Andy Murray 7-6(4) 6-3
In a match that definitely had some unpredictability, Hurkacz proved doubters wrong, by taking Murray in a very close first set, but a more convincing second set. The 9th seed is beginning to form another good Masters 1000 Title. This sort of consistency is what has been lacking, but now he has a chance to get into the top 10, and he is taking his career more serious than ever.
Andrey Rublev (4) d Marin Cilic 5-7 6-3 6-1
This was a very expected outcome here, as Cilic can beat anyone in a solid first set. As the match went into it's second hour, Rublev just overpowered Cilic, forcing errors, but Cilic also making many unforced errors to help Rublev roll over easily in the final two sets.
Casper Ruud (8) d Reilly Opelka 6-7(5) 6-0 7-6(4)
In a match that saw Opelka's first ever bagel (6-0) on a hard court surface, the 8th seed came back in an insane 20minute second set with Opelka only winning 6 points. The match did however go down to the wire, but with Ruud leading the tiebreak 4-0, it was hard to see him lose it. Ruud actually serving more aces than Opelka! (21-17).
Daniel Medvedev (1) d Mackenzie McDonald 6-2 6-2
Medvedev continues his impressive run, having a boring straight sets win over Mackie McDonald. Medvedev winning 93% on his first serve, making a convincing victory in exactly 1hour!
John Isner d Jannik Sinner (11) 5-7 7-6(4) 6-4
In possibly the match of the day, big John fights back from a set down to overcome the 11th seed. Isner only served 2 more aces than the 20yo (12-10), but Isner's groundstrokes winded back the clock like he was 20! Only 1 break each during the match hitting 2hrs 30m. Isner is really loving it here!
Alexander Zverev (3) d Lloyd Harris 7-6(3) 6-2
There were question marks surrounding Zverev's form after such a high winning Gold in Tokyo, but he showed his grounded nature, not getting overly emotional like he can be seen. Both players competed well, but it was the 3rd seed creating and converting break points (2/3) with the South African not able to create any.
Lorenzo Sonego d Tommy Paul 7-6(9) 6-2
Not even fired up American college fans could get Tommy Paul over the line today. Sonego had enough fire in his heart to burn Paul in the first set, which finished him for the match. Sonego serving 13 aces to 6 and winning 82% of first serves, converting 66% (2/3) of break points compared to 0% (0/5) for the American.
Gael Monfils d Alex De Minaur (14) 6-3 7-5
In another contender for match of the day, neither players are competing at top level, but Monfils is becoming the more in-form player as of late. Monfils just creating those break points (13) compared to just 3 for the Aussie. Monfils has been playing some inspiring tennis recently, but it is difficult to see him beating his next opponent, 4th seed Andrey Rublev.
Diego Schwartzman (10) d Frances Tiafoe 6-1 4-6 6-4
Schwartzman had an inspired victory against Dan Evans, and continues to love three set matches. In both matches he has won the first set, lost the second, and won the third, so it will be interesting how he goes against Casper Ruud (8) who finished a monster match against Opelka.
Stefanos Tsitsipas (2) d Seb Korda 7-6(5) 6-3
The second seed advanced 7-6(5), 6-3 after one hour and 39 minutes, setting a clash against Italian Lorenzo Sonego. It was Tsitsipas' first win at the Lindner Family Tennis Center in Cincinnati.
"He’s someone who has been doing well recently. I knew I had a difficult challenge ahead of me," Tsitsipas said of Korda in his on-court interview. "When things got tough, I stayed there. The match was played in the details.
"I was able to bring the best out of my game when things got tough and persevere. I was consistent throughout the important moments and I think just trying to find solutions and ways to apply as much pressure as possible. That was the key element today."