There were some upsets at the ATP Western and Southern Open on Tuesday, with five seeds falling in Cincinnati.
Though John Isner and Pablo Carreno Busta advanced, David Goffin and Tomas Berdych notably stumbled in their opening round matches, losing to Nick Kyrgios and Juan Martin del Potro respectively.
Meanwhile, American wildcard Jared Donaldson claimed another big scalp in an ATP 1000 tournament, defeating Roberto Bautista Agut in straight sets.
Jack Sock and Jo-Wilfried Tsonga also fell to unseeded opponents, with Yuichi Sugita and Ivo Karlovic progressing.
KYRGIOS BREEZES THROUGH
Neither looked in optimal condition, but Nick Kyrgios was nevertheless in fine touch against ninth-seeded Belgian David Goffin, winning 6-2 6-3.
Securing the win in 66 minutes, the unseeded Australian was cleanly hitting the ball and Goffin - who took a medical time-out for a knee injury - was in no condition to quickly cover the court.
Kyrgios had little trouble on serve, winning 87 per cent of points on his first serve.
In the next round, he will meet Ukrainian qualifier Alexandr Dolgopolov, who dispatched Kevin Anderson 6-4 7-6 (8-6).
DONALDSON FORM CONTINUES
Jared Donaldson claimed a second top 20 scalp in consecutive weeks, beating Roberto Bautista Agut 7-6 (7-5) 6-3.
After defeating Lucas Pouille and Benoit Paire in Montreal, the American wildcard served 11 aces and saved four of six break points against the Spanish world number 14.
With a long list of withdrawals, Donaldson can go on another encouraging run, but he will have to defeat Indian lucky loser Ramkumar Ramanathan.
DELPO STORMS HOME
After a four-year absence from Cincinnati, Juan Martin del Potro made a triumphant return, defeating Tomas Berdych 3-6 7-6 (6-1) 6-0.
Del Potro, a semi-finalist in 2012 and 2013, fought back after the Czech 10th seed settled into an early service rhythm.
Broken when serving for the second set at 5-3, the 30-year-old Argentine regrouped and controlled the match from the tie-break against Berdych, who is coming back from a rib injury.
The former US Open champion will now face American qualifier Mitchell Kreuger.
Fognini handed Thiem the early ascendancy, with a double fault on break point in his opening service game.
Despite double faulting twice on his own serve in the next game, Thiem consolidated the break.
The uninspired Italian world number 25 was evidently that revolted by his inability to break back, he even expelled bodily intake, leading to a lengthy stoppage.
The Austrian third seed took control following the uncommon time-out, and broke in the opening game of the second set to eventually triumph 6-3 6-2.