Richard Gasquet earned a meeting with incoming world number one Rafael Nadal at the ATP Western and Southern Open, while Sam Querrey cruised into the second round.
Frenchman Gasquet accounted for qualifier John-Patrick Smith at the ATP 1000 tournament in Cincinnati on Monday.
Gasquet's routine victory secured a showdown with top seed Nadal as he looks for his first win in 15 matches against the Spaniard.
American 15th seed and Wimbledon semi-finalist Querrey eased past Stefan Kozlov in straight sets.
Fellow American Frances Tiafoe will take on in-form Alexander Zverev in the next round after ousting qualifier Maximilian Marterer.
GASQUET MAKES LIGHT WORK OF AUSSIE
Smith was no match for Gasquet, who posted a 6-4 6-4 victory in the opening round.
Gasquet - coming off a three-set loss to Coupe Rogers champion Zverev in Montreal - broke four times in one hour, 25 minutes.
Countryman Jo-Wilfried Tsonga will open his campaign against Ivo Karlovic, who outlasted Jiri Vesely 6-3 3-6 7-5.
QUERREY SAILS INTO NEXT ROUND
It was a routine outing for Querrey as he dispatched Kozlov 6-3 6-0.
Querrey dropped only four points on serve and did not face a break point as he awaits the winner of Robin Haase versus Adrian Mannarino.
Countryman Tiafoe will face Zverev next after defeating Marterer 6-3 7-6 (7-2).
Tiafoe did not face a break point against the German.
The Spaniard lost in a battle of the lefties, suffering a 6-4 6-4 loss to Mischa Zverev.
In the pair's first meeting in nine years, Zverev did not face a break point and only dropped four points on his first serve.
Zverev will play either 11th seed Pablo Carreno Busta or Paolo Lorenzi in the second round.
Feliciano Lopez and Fabio Fognini were among the other players to progress.
PAIRE PULLED APART BY QUALIFIER KRUEGER
There was a stunning result as Benoit Paire, ranked 41 in the world, was hammered 6-2 6-1 in less than an hour by qualifier Mitchell Krueger.
The American, ranked over 200 places below his opponent, made light of that disparity to ease into the second round, where he will face either Tomas Berdych or Juan Martin del Potro.
It was Krueger's first main-draw victory of 2017, sealed with two breaks of serve to end the first set, before he reeled off four successive games to see out the match.