SHANGHAI – Jannik Sinner avenged his loss to Ben Shelton in the fourth round of last year's Shanghai Masters with a 6-4, 7-6 (1) victory, spoiling the 22-year-old American's birthday on Wednesday.

Like last year, the duel was again characterized by incredible shots and serve dominance, but this time the 23-year-old Italian prevailed and improved his record against Shelton to 4-1.

“Happy how I handled this situation. “It’s obviously a position I was in last year and where I am now it’s different so I’m happy to be in the position I’m in,” Sinner said.

Sinner's break in the ninth game was all that separated the duo in the first set. Both players then dominated on serve until the second round before the Italian raced away in the tiebreak and won the last seven points of the match to advance to his seventh ATP Masters 1000 quarterfinal of the year.

He will play against fifth-seeded Daniil Medvedev, who previously defeated his long-time rival Stefanos Tsitsipas 7-6 (3), 6-3, in a match in which the Greek player went on a lengthy, minute-long tirade against referee Fergus Murphy started out and initially refused to continue playing.

In a similar incident the day before, Frances Tiafoe repeatedly insulted a referee after losing his third-round match and later apologized.

Second seed Carlos Alcaraz, who won the China Open in a thriller against Sinner last week, notched his 12th straight win with a challenging 6-4, 7-5 victory over French veteran Gael Monfils to advance to the quarterfinals.

Alcaraz needed all his shooting skills to outmaneuver the 38-year-old Monfils. The 21-year-old Spaniard scored 22 winners and took a break in every set to decide the match in 87 minutes.

The French Open and Wimbledon winner will face Tomas Machac in the quarterfinals.

Four-time champion Novak Djokovic continued his quest for a 100th career title with a 6-3, 6-2 victory over 61st-ranked Roman Safiullin, but third-seeded Alexander Zverev lost to David Goffin 6-4, 7-5 Belgium.

The 33-year-old Goffin will face seventh seed Taylor Fritz for a place in the semifinals. Fritz defeated Dane Holger Rune 6:1, 6:2 to secure his place in the last eight.