Heather Watson began the defence of her Monterrey Open title with a hard-fought win over Serbia’s Nina Stojanovic.
The British number three bounced back from losing a tight second-set tie-break to eventually triumph 6-2 6-7 (7/9) 6-4 in a match lasting almost three hours.
It marked a welcome return to winning ways for Watson, who has struggled for form this year and crashed out in the first round in Miami last week.
She is currently down at 125 in the world, having threatened the top 50 after beating Kirsten Flipkens to claim her third career title in the same tournament last year.
Watson broke Stojanovic twice to take the first set, but the pair swapped two breaks apiece as a tighter second set headed into a tie-break.
The Briton led 5-2 and looked set for a straight-sets win before her opponent hit back to take the game into a decider.
Grabbing an early break, Watson then saved a break point on her way to establishing a 5-3 lead, then held her nerve to serve out to love and take victory.
Watson will next face sixth seed Ekaterina Makarova with the possibility of taking on world number one Angelique Kerber in the quarter-finals.
Makarova needed just over an hour to overcome Denisa Allertova 6-4 6-3 and reach round two.
There was a surprise defeat for eighth seed Christina McHale, who was beaten 6-3 5-7 6-4 by Czech qualifier Tereza Martincova.
Fifth seed Timea Babos had no problems dispatching another qualifier, Holland’s Lesley Kerkhove, 6-1 6-3.
Meanwhile, Australian Open semi-finalist Mirjana Lucic-Baroni was a first-round winner at the Volvo Car Open in Charleston on Tuesday.
The 11th seed old fought off a plucky comeback by qualifier Aleksandra Krunic to triumph 6-1 4-6 6-3 in just under two hours.
Romanian 10th seed Irina-Camelia Begu celebrated returning to her favoured clay with a ‘double bagel’ 6-0 6-0 win over Cagla Buyukakcay of Turkey.
China’s Shuai Zhang was another seed in early action as she beat Misaki Doi of Japan 6-2 6-1 in just over an hour.
But American 14th seed Lauren Davis was beaten 7-5 6-4 by world number 91 Maria Sakkari of Greece.