Jannik Sinner edged Brazilian teenager João Fonseca 7–6 (8/6), 7–6 (7/4) in a thrilling Stadium Court clash on Tuesday to reach the quarter-finals of Indian Wells Open.

The first meeting between world number two Sinner and the big-hitting 19-year-old lived up to expectations, producing a high-quality contest that drew a raucous atmosphere from a crowd packed with enthusiastic Brazilian supporters.

Sinner will next face another fast-rising youngster, 20-year-old American Learner Tien, for a place in the semi-finals.

Fonseca went toe-to-toe with the Italian in a tense opening set but was unable to convert his lone break opportunity, while Sinner also failed to capitalize on two chances of his own.

A couple of uncharacteristic errors from Sinner helped Fonseca surge to a 6–3 lead in the tie-break, but the Italian responded strongly. He saved one set point with a powerful ace before reeling off five straight points to claim the set.

Sinner appeared on course for a comfortable victory after breaking for a 4–2 lead in the second set, but Fonseca refused to fade quietly.

The Brazilian broke Sinner to love in the ninth game and held to level at 5–5, forcing a second tie-break.

An ace handed Fonseca a 4–3 advantage in the decider, but Sinner again found another gear, winning four consecutive points and sealing the match with a superb forehand return.

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

“João is 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,” he added.

Tien booked his place in his first Masters 1000 quarter-final after saving two match points to defeat Spain’s Alejandro Davidovich Fokina 4–6, 6–1, 7–6 (7/4).

“Honestly, after saving match points going into the tie-break, it felt like I was playing with house money — I really had nothing to lose,” said Tien, a Southern California native who remembers attending the tournament as a child.

Elsewhere, Arthur Fils continued his strong comeback from injury by upsetting ninth-seeded Canadian Felix Auger-Aliassime 6–3, 7–6 (11/9) to set up a quarter-final meeting with Germany’s Alexander Zverev.

Zverev secured his place in the last eight with a 6–3, 6–4 victory over American Frances Tiafoe.

Fils has now reached the Indian Wells quarter-finals for the second straight year, though his path back to the latter stages has been anything but straightforward.

Back trouble sidelined the 21-year-old for eight months, but since returning to competition in Montpellier last month he has impressed, including a run to the final in Doha.

Currently ranked 32nd in the world, Fils looked set for a comfortable victory when he led 4–2 in the second set. However, he lost momentum and soon trailed 0–5 in the tie-break before regaining his composure.

The Frenchman saved five set points before eventually closing out the match in straight sets.

“I was at 0–5 in the tie-break and I was going to my box and complaining and complaining,” Fils said, adding that his team advised him to stop complaining and refocus on the match.

“I tried to focus as best I could. Not too much emotion, celebration — just tunnel vision. I’m happy with it,” he said, later celebrating the victory with a powerful chest thump after converting match point.