Britain’s Kyle Edmund raced into the third round while several seeded players were knocked out at the Winston-Salem Open in North Carolina.
The British number one took three breaks of serve to claim a 6-3 6-3 victory over Argentina’s Leonardo Mayer.
In a dominant serving performance, the number three seed won 93 per cent of points on his first serve and did not face a single break point in the match.
He will now face Roberto Carballes Baena in the last 16 after the Spaniard beat compatriot and number 13 seed Albert Ramos-Vinolas.
The pair exchanged breaks in the opening two games of the match, before Carballes Baena captured the momentum and broke another three times to clinch the opening set.
He needed just one break of serve in the second to seal a 6-1 6-3 win.
Carballes Baena was one of four players to eliminate seeded opponents on day four, with another Spaniard, Jaume Munar, seeing off Russia’s Andrey Rublev 6-3 6-2.
Munar won 61 per cent of his second serve points on his way to defeating the number 11 seed, booking a last 16 tie with Steve Johnson.
The American number eight seed saved the only break point he faced to see off compatriot Tommy Paul, a qualifier, 7-6 6-2.
Meanwhile, tenth seed Nikoloz Basilashvili lost 7-5 6-3 to Italian Matteo Berrettini while Australian Alex De Minaur, the 15th seed, went down 6-3 6-3 to Daniil Medvedev.
Sixth seed Hyeon Chung fought past Spain’s Guillermo Garcia-Lopez 7-6 (7/4) 6-2, while lucky loser Dominik Koepfer beat Tennys Sandgren 6-2 7-6 (7/5).
Germany’s Peter Gojowczyk, the 16th seed, was taken to three sets by Argentinian qualifier Horacio Zeballos before eventually prevailing 6-4 6-7 (4/7) 6-1.
Two games were suspended for the day after rain stopped play, with Pablo Carreno Busta leading Franko Skugor 6-3 6-6 and Guido Andreozzi ahead 6-4 2-3 against Radu Albot.