Carlos Alcaraz and world No.1 Jannik Sinner showed no signs of fatigue from their China Open final earlier this week to advance with straight-set victories in their opening matches of the Shanghai Masters.

The second-ranked Alcaraz, who beat the Italian in Beijing on Wednesday for his fourth title of the year, recorded his 10th consecutive win with a 6-2 6-2 result on Saturday against 19-year-old Chinese player Shang Juncheng.

The 21-year-old Spaniard won the first nine points of the match and four of seven break points as he rushed into a third-round meeting with another Chinese player, Wu Yibing.

"I'm not used to playing against players younger than me," Alcaraz said.

"He has been playing good tennis lately, lifting his first ATP (title in Chengdu), so I'm pretty sure he's going to climb the rankings. I'm just happy to be able to win these kinds of matches."

Sinner, who is dealing with an ongoing doping case, had a comfortable 6-1 6-4 win over Japan's Taro Daniel for his 250th career victory.

The Italian, who won the US Open last month for his second major of the year, fired 12 aces and 38 winners.

"I felt quite comfortable today," said 23-year-old Sinner, who next plays Tomas Martin Etcheverry of Argentina.

"I feel in good shape also physically, which is very important for me. Of course I will try to improve for tomorrow's performance, but today I was serving really, really well, especially in important moments, and was moving well."

In other matches on Saturday, 24th-ranked Alexei Popyrin of Australia beat Serbia's Miomir Kecmanovic 6-3 6-2.

World No.65 Jakub Mensik of the Czech Republic broke sixth-ranked Russian Andrey Rublev seven times on his way to an upset 6-7 (7-9) 6-4 6-3 victory.

Yosuke Watanuki also had a surprise win, beating world No.35 Brendan Nakashima 7-6 (7-4) 6-3. The Japanese qualifier next plays either seventh-ranked American Taylor Fritz or French qualifier Terence Atmane.