Defending US Open champion Jannik Sinner effortlessly took out Australian Alexei Popyrin 6-3, 6-2, 6-2 to make the third round of the grand slam on Thursday and send out an ominous warning to his title rivals in New York.

Talking about rivals, second seed Carlos Alcaraz overcame a mid-match worry over his knee to swat aside Italy's Luciano Darderi 6-2, 6-4, 6-0 on Friday.

So far in New York this year, Sinner and Alcaraz, the two arch-rivals, have seemed to be in a different league from the rest of the field.

Sinner, the metronomic world No. 1, looking to become the first man to retain the trophy at Flushing Meadows since Roger Federer won the last of his five crowns in 2008, was expected to face a tricky test against a tenacious opponent but romped to victory.

Sinner’s 23rd consecutive match victory at hardcourt grand slams improved his overall record to 41-9, matching the mark of Swiss great Federer in his first 50 matches on the surface at the majors.

“Obviously, I try to play the best tennis I can,” said Sinner, who plays Canadian 27th seed Denis Shapovalov in the next round. “The first round matches are always different compared to the further you go (in the tournament).

“I’m very happy that I managed these matches as good as I could... when you are up two sets and a break, you try to serve as best as you can... I’m aiming to improve on the serve but the rest (of my game), I’m quite comfortable with.”

The usually understated Sinner will now have a day to recover and said he had a number of Italian restaurants in mind to indulge his appetite.

“I know some good Italian places here and I have three or four restaurants that we switch between. New York provides great restaurants and the people are very nice."

Knee scare

Alcaraz's win over Darderi was his 80th in grand slams. The Spaniard has been on an extraordinary run, with a 42-2 record since April, and pushed on after taking a second-set medical timeout on Arthur Ashe Stadium.

Alcaraz told the staff member that he had begun to feel something wrong with his right knee earlier in the set. But it did not affect his game.

"It's just a precaution that I asked for the physio," Alcaraz said after the match, tamping down concerns. "I'm feeling good." The 2022 champion further said: "I just played such great tennis, great performance in general, so I'm just really proud about it."

With inputs from Reuters