INDIAN WELLS (AFP) -- Top seed Carlos Alcaraz reached the Indian Wells quarterfinals Tuesday, March 14, as Britain's Jack Draper retired from their fourth-round match with an injury to his right side.

Spain's Carlos Alcaraz hits a forehand return to Britain's Jack Draper during their Indian Wells Masters round of 16 tennis match in Indian Wells, California, on March 14, 2023. (AFP)

Spain's Alcaraz, who can return to number one in the world with a third ATP Masters 1000 title this week, led 6-2, 2-0 when Draper, who had been treated by a physio, called a halt after 46 minutes on court.

"This is not the way anybody wants to win a match, because something is wrong," Alcaraz said. "All I can say is I hope to see him get well soon."

Alcaraz, 19, became the youngest men's world number one ever last year after his precocious US Open triumph.

But after an abdominal injury hindered him late last year and a leg injury forced him to miss the Australian Open he has slipped behind Serbian superstar Novak Djokovic.

Djokovic is absent this week as he is prohibited from entering the United States because he declined to be vaccinated against Covid-19.

Alcaraz said he's focused on winning a first Indian Wells title, and will let the ranking take care of itself.

He returned to action last month with a victory in Buenos Aires and a runner-up finish in Rio de Janeiro -- where he suffered a strained hamstring that prompted him to pull out of Acapulco.

He's looked in fine form in Indian Wells, taking a 2-0 lead in the first set after escaping 0-40 in his opening service game.

"I felt the ball really well," Alcaraz said. "I'm really happy with that part.

"I would say I returned well, I hit great shots. I finished the match with confidence in my shots, to come into the next round with more confidence."

Draper, his serve speed dropping and his movement slowed, was seen by the physio between sets and pulled the plug after winning just one point in the first two games of the second.

It was a disappointing finish to the week for Draper, who beat childhood hero Andy Murry in the third round.