Tommy Paul had to retire from his second-round match at the Miami Open after pulling up with an ankle injury. Fans were left shocked when the American No. 2 picked up the freak injury during a rally against Martin Damm. Paul was one of the favourites to have a strong showing in Miami but his campaign came to a sudden end as he couldn't continue playing.

The world No. 14 came in fresh off the back of a run to the Indian Wells semi-final and picked up where he left off, taking the first set over countryman Damm in his opening match.

While serving in the fourth game of the second set, Paul ran to the net to chase down the ball but suddenly started hopping off the court, visibly struggling with something in his left leg. The crowd on Court 7 gasped as the 26-year-old sat on the floor and eventually moved onto his bench, grabbing his ankle as the physio came over.

But there was no way Paul could keep playing as he struggled to put any weight on it. The 13th seed decided to retire while leading 6-4 1-2, shaking hands with his opponent. Damm is making his Masters 1000 debut as a wildcard this week.

He earned his first tour-level victory over Zhizhen Zhang in the first round and now finds himself in the last 32. Damm will now face either Frances Tiafoe or Christopher O'Connell.

The Miami Open has been hit by several retirements in the main draw and qualifying event this week. And another player forfeited their match within moments of Paul on Saturday.

Zhu Lin retired while 4-6 1-4 down to No. 5 seed Jessica Pegula. The world No. 63 called the doctor and physio to the court when she started feeling dizzy and decided that she wasn't well enough to continue. She's not the first player to struggle with the heat and humidity in Miami this week.