INDIAN WELLS (AFP) — Four-time major champion Jannik Sinner edged talented Brazilian teenager Joao Fonseca 7-6 (8/6), 7-6 (7/4) in a scintillating Stadium Court clash on Tuesday to reach the quarterfinals at Indian Wells.

The first meeting between the world No. 2 Sinner and the big-hitting 19-year-old lived up to expectations, the fireworks sparking a raucous response from a crowd packed with enthusiastic Brazilian fans.

Sinner will face another fast-rising youngster in 20-year-old Learner Tien of the United States for a place in the semifinals.

Fonseca went toe-to-toe with the Italian in a tense first set but was unable to convert his lone break chance and Sinner failed to capitalize on two.

A couple of uncharacteristic Sinner errors helped Fonseca power to a 6-3 lead in the tiebreaker, but the Italian responded, denying one set point with an ace to launch a run of five straight points that sealed the set.

Sinner looked headed to a comfortable victory with a break for 4-2 in the second, but Fonseca wasn’t about to go quietly.

He broke Sinner to love in the ninth game and held for 5-5 as they went to a second tiebreaker.

An ace gave Fonseca a 4-3 lead in the decider, but Sinner surged home with four straight points, polishing off the win with a masterful forehand service return.

“I felt like trying to be as aggressive as possible was the key,” said Sinner, who is chasing a first title in the prestigious Masters 1000 event in the California desert.

“Joao’s an incredible talent, very powerful from both sides. He was serving very well.”

“Maybe he dropped a little bit at the end of the second set, but I’m very happy to get through,” Sinner added.

Tien saved two match points to reach his first Masters 1000 quarter-final with a 4-6, 6-1, 7-6 (7/4) victory over Spain’s Alejandro Davidovich Fokina.

“Honestly, after saving match points going into the tiebreak, just felt like I was playing with house money almost, really had nothing to lose,” said Tien, a Southern California native who has fond memories of attending the tournament as a child.

Arthur Fils’s injury comeback gathered pace as the Frenchman upset ninth-ranked Canadian Felix Auger-Aliassime 6-3, 7-6 (11/9) to book a quarterfinal meeting with fourth-ranked Alexander Zverev.

Germany’s Zverev downed American Frances Tiafoe 6-3, 6-4.

Fils is in the Indian Wells last eight for the second straight year, but it’s been a twisting road to arrive there.

Back trouble kept him off the courts for eight months, but since a return at Montpellier last month he has impressed with a run to the final in Doha.

The 21-year-old, now ranked 32nd in the world, appeared to be in control with a 4-2 lead in the second set. But he let that advantage slip away and trailed 0-5 in the tiebreaker before he steadied, saving five set points before wrapping up the straight-sets win.

“I was at 0-5 in the tie-break and I was going to my box and complaining and complaining,” he said, adding that the advice he got was to stop complaining and focus on the match.

“I tried to focus as best I could. Not too much emotion, celebration. Just tunnel vision and I am happy with it,” said Fils, who let the emotion emerge again with a mighty chest thump after putting away a match point.