Britain's Jacob Fearnley entered the second round of the Miami Open with a 7-6 (8), 2-6, 6-4 win over France's Benjamin Bonzi on Thursday.
It was the 23-year-old's first ATP Masters win and he had to push himself to his physical limits to earn it. He was beset with a leg injury in the second set and took a medical timeout ahead of the third one to get treatment for his left hip.
But, he rallied on and earned himself a second-round showdown against world No. 2 Alexander Zverev. The two recently met at the Australian Open, where the German won in straight sets.
"That was extremely difficult, I was feeling my legs, especially my left leg twitching a little bit when I moved to a forehand," Fearnley told Sky Sports of his win.
"Just had to dig deep and luckily I got the break at the start of the third because I think that could have easily got away from me. Super happy to get the win and to move on."
Meanwhile, Cameron Norrie suffered a first round exit in Miami after a 6-4, 6-2 loss to Yunchaokete Bu.