Sinner and Alcaraz advance in straight sets to stay on course for Qatar Open showdown

Sinner, the world No. 2, advanced to the quarter-finals by defeating Australia's Alexei Popyrin 6-3 7-5.

"I struggled a little bit. He raised his level and I missed a couple of quite easy shots, but this can happen; I lost a bit the rhythm and a bit of confidence. You'll have to find different ways to win matches so I'm really happy, now we have to aim to raise our level."

Shortly after Sinner's victory, Alcaraz dispatched France's Valentin Royer 6-2 7-5 to continue his title bid.

The two rivals contested six finals last season, including three at Grand Slam events. Alcaraz, currently ranked No. 1, emerged victorious at both the French Open and the US Open.

"Well, in the end, I think having Jannik in the draw is always good," Alcaraz said. "You always want to keep pace. Hopefully, we can reach a final. I think those are the moments you work for, to reach the final rounds, whoever it is."

Next up for the 22-year-old Spaniard is a quarter-final meeting with Karen Khachanov, who came through a three-set battle against Marton Fucsovics, winning 6-2 4-6 6-4.

Sixth seed Jakub Mensik moved smoothly into the last eight with a 6-3 6-2 win over Zhang Zhizhen and will now take on Sinner. 

The Italian has reached at least the quarter-finals in 28 of his last 30 tournaments, a run that dates back to the 2023 ATP Finals in Turin.

The 24-year-old, who captured both the Australian Open and Wimbledon titles last year, has also won 22 of his past 23 matches. His sole loss during that stretch came against Novak Djokovic in last month's Australian Open semi-finals.

Elsewhere in Doha, Greece's Stefanos Tsitsipas produced an upset by defeating world No. 11 Daniil Medvedev 6-3 6-4. Tsitsipas will now face fifth seed Andrey Rublev, who beat Fabian Marozsan 6-2 6-4.

Rounding out the quarter-final field are unseeded Frenchman Arthur Fils and eighth seed Jiri Lehecka, both of whom progressed with comfortable wins.

READ MORE: Novak Djokovic confirmed for Indian Wells return