Kyle Edmund moved through to the second round of the New York Open but Kevin Anderson crashed out, while Argentina Open champion Marco Cecchinato fell at the first hurdle.
Edmund – the eighth seed – defeated Japanese opponent Yasutaka Uchiyama 7-5 6-4 at the ATP Tour 250 tournament on Tuesday.
The Brit won 86 per cent of his first serves as he earned a clash with Dominik Koepfer after one hour, 44 minutes.
German Koepfer defeated last year's runner-up Brayden Schnur 7-5 6-4 in the opening round.
First #NYOpen
— #NYOpen (@NewYorkOpen) February 11, 2020
First #NYOpen2020 win
@DominikKoepfer knocks out last year’s finalist Brayden Schnur 6-4, 6-3 @atptour pic.twitter.com/4lUjp2eYaY
Kevin Anderson – the 2018 champion in New York – was stunned 7-6 (8-6) 6-4 by qualifier Jason Jung, who will face Cameron Norrie after the seventh seed beat Brian Shi 7-5 6-3.
Elsewhere, Jordan Thompson accounted for veteran Ivo Karlovic 6-3 7-6 (7-2), Yoshihito Nishioka outlasted Henri Laaksonen 6-3 0-6 6-2, Paolo Lorenzi prevailed 4-6 6-4 6-0 over Danilo Petrovic and Go Soeda went down 6-2 6-7 (2-7) 6-3 to Kwon Soon-woo.
At the Argentina Open, Cecchinato's title defence was ended by Roberto Carballes Baena in the first round.
Cecchinato was upstaged 6-4 7-6 (7-3) by Carballes Baena, who saved five of six break points on the clay in Buenos Aires.
Next up is Casper Ruud after the eighth seed blitzed Pablo Andujar 6-2 6-3.
Fellow seed Laslo Djere and Albert Ramos-Vinolas also progressed to the last 16, along with Facundo Bagnis, Juan Ignacio Londero, Pedro Sousa, Pedro Martinez and Jozef Kovalik.