Jo-Wilfried Tsonga toiled to a straight-sets victory over Victor Troicki in difficult conditions to advance to the third round of the Sony Open.
In rising heat and with a blustery wind unsettling both players at times, it was not the prettiest of victories but the sixth seed prevailed 7-6 (8/6) 6-3.
Serving at 5-4, Troicki failed to take advantage of a set point and instead netted as Tsonga levelled before the match moved into a tie-break.
If rankings were a cast iron guide, the match between world number 10 Richard Gasquet and Olivier Rochus, ranked 135 places lower, should have been a formality for the Frenchman.
However, the eighth seed was matched throughout the first set before racing away with the second for a 7-5 6-2 victory in an hour and 27 minutes.
Andreas Seppi, 16th seed, came through an energy-sapping match to beat Aljaz Bedene 7-5 5-7 7-5 while Sam Querrey, seeded 17th, came from a set down to beat Poland's Lukasz Kubot 6-4 6-3 6-3.
Kubot served out the first set with an ace with Querrey responding in kind to level the game at one set all. A looping shot into the corner saw the American through.
However, 18th seed Philipp Kohlschreiber exited the tournament as David Goffin claimed a 7-6 (7/5) 4-6 6-2 win and 27th seed Martin Klizan was sent packing by Jarkko Nieminen 6-2 6-2.
Fernando Verdasco and Jerzy Janowicz were other seeds to tumble out, the former going down 6-3 7-6 (8/6) to Colombian Alejandro Falla while Brazil's Thomaz Bellucci saw off Janowicz 7-6 (7/5) 3-6 6-3.
John Isner also looked in danger of being knocked out when he lost the opening set to Ivan Dodig. However, the big-serving American, seeded 20th, battled back to record a 4-6 7-5 7-6 (7/5) triumph.
Meanwhile, Tomas Berdych also had to do things the hard way against Spain's Daniel Gimeno-Traver, the fourth seed eventually coming out on top by a 5-7 7-6 (7/3) 6-2 scoreline at Crandon Park.
Marin Cilic, Nicolas Almagro and Milos Raonic also advanced, courtesy of respective straight-sets victories over Santiago Giraldo, Guido Pella and Guillaume Rufin.