Serbian fifth seed Dusan Lajovic fought back from a set down to triumph over Benoit Paire in the Argentina Open first round while Spanish veteran Fernando Verdasco also progressed on Monday.
Lajovic, who is currently ranked 37th in the world, beat 50th-ranked Paire 4-6 6-4 7-6 (7-3) in just over two hours in Buenos Aires.
In a tight match, the Serbian got the edge in the third-set tiebreak as his first serve seldom let him down.
Former top 10 player Verdasco, now 38-years-old, defeated Bolivian Hugo Dellien 6-4 3-6 6-1 in two hours and two minutes.
Serbian eighth seed Laslo Dere got past compatriot Miomir Kecmanovic 6-4 1-6 6-1, while Argentine pair Federico Coria and Francisco Cerundolo also progressed.
Meanwhile at the Dallas Open, veteran South African Kevin Anderson proved too good for Sam Querrey 6-4 6-4.
The 35-year-old former US Open and Wimbledon finalist sent down 21 aces as he won in little over an hour.
Emerging American Brandon Nakashima defeated Australian John Millman 7-5 7-6 (7-3) in the first round.