Carlos Alcaraz had to dig deep to book his place in the Olympic Games semi-finals with a straight-sets win over Tommy Paul.

The Spaniard looked to be heading for a decider until a brilliant second-set comeback saw him win 6-3 7-6 (9-7) on Court Philippe Chatrier in two hours and one minute.

Alcaraz was looking to quickly put his disappointing doubles exit with Rafael Nadal behind him and successfully defended two break points in the opening game.

While Paul matched him stride for stride during the opening stages, the Spaniard got the all-important break in game six to edge in front before taking the first set.

His momentum soon faltered though, as the American raced into a 3-0 lead in the second and looked to be cruising.

Alcaraz's fighting spirit soon came to the fore as he got another vital break during a three-game winning run to level the score and eventually, force a tie-break.

The 21-year-old then rounded off an incredible comeback by saving a set point during the tie-break and winning the final three points.

He will play either Norway's Casper Ruud or Canada's Felix Auger-Aliassime in the semi-finals.

Data Debrief: Alcaraz stays on track for gold

Alcaraz is the fourth-youngest player to reach the men's singles semi-finals at the Olympics since 1988 (21 years and 83 days), and the youngest since Novak Djokovic in Beijing 2008.

He has now won his last 11 matches on the bounce, winning each of the last four in straight sets.

Alcaraz beat Paul en route to his Wimbledon title last month, and he will be hoping that is a good omen as he chases a gold medal in his debut Olympics.