Carlos Alcaraz inched a step closer to defending his Wimbledon title with a hard-fought victory over Ugo Humbert.

The 21-year-old Spaniard held off a late charge from 16th seed Humbert to win 6-3 6-4 1-6 7-5 and move into the last eight at SW19.

It took Alcaraz's winning streak at Grand Slams to 11 following his French Open triumph last month.

"I feel great playing today, I think I played a really high level," he said.

"Playing a leftie, I try not to think about it and play my own game."

Alcaraz will next face American 12th seed Tommy Paul, the Queen's Club champion, who defeated Spain's Roberto Bautista Agut 6-2 7-6 (7-3) 6-2.

Meanwhile, world number one Jannik Sinner defeated American 14th seed Ben Shelton 6-2 6-4 7-6 (11-9).

Shelton, who won in five sets in his first three rounds, had four set points in the third-set tie-break.

Sinner, 22, will play Daniil Medvedev next after the Russian fifth seed benefitted from Grigor Dimitrov's early retirement with a leg injury.

The Bulgarian 10th seed took a medical timeout before deciding, at 5-3 down in the first set, not to continue.