Jannik Sinner outlasts Joao Fonseca in Indian Wells thriller, Carlos Alcaraz through

The 19-year-old Fonesca was relentless in his energy and was only Sinner's experience in the clutch moments that saw him emerge the victor via a 7-6(6), 7-6(4) scoreline on the hard courts of Indian Wells.

The Brazilian was brilliant behind his powerful serve, smashing hi way to a 6-3 lead in the tiebreak. But Sinner reeled off five consecutive points to steal the set.

It looked to be a straightforward second set for Sinner when he wn the sixth game to go 4-2 up, but Fonesca broke back and forced another tiebreaker. And again, the Italian was clutch, winning the final four points of the match to seal his place in the final eight.

"Joao is an incredible player, incredible talent, very powerful from both sides. He was serving very well," Sinner said after the match

"I felt like trying to be as aggressive as possible was the key. I dropped a bit of intensity at the end of the second set but he played incredible tennis out there. The atmosphere has been amazing, so I'm very happy about today's match."

Sinner will next face 25th seed Learner Tien in Thursday's quarterfinals.

Earlier, top seed Carlos Alcaraz turned a difficult situation into a runaway victory with a scintillating 6-7(6), 6-3, 6-2  win over Frenchman Arthur Rinderknech, while fourth seed Alexander Zverev was tto good for Frances Tiafoe, winning 6-3, 6-4.

READ MORE: Johannesburg Giants coach confident ahead of BAL