Jannik Sinner, Carlos Alcaraz breeze through Shanghai openers ...

SHANGHAI -- Carlos Alcaraz and top-ranked Jannik Sinner showed no signs of fatigue from their China Open final this week as they advanced in Shanghai with comfortable straight-set victories in their opening matches.

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

The 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 to be able to win these kinds of matches."

Sinner, who is dealing with a doping case, had a comfortable 6-1, 6-4 outing against Taro Daniel of Japan for his 250th career win.

Sinner, 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 Sinner, who next plays Tomas Martin Etcheverry of Argentina. "I feel in good shape, which is very important for me. I was serving really, really well, especially in important moments, and was moving well."

Third-ranked Alexander Zverev began with a 6-4, 6-2 win over Italian qualifier Mattia Bellucci, while fourth-ranked Novak Djokovic had a tougher task prevailing 7-6 (3), 7-6 (9) over Alex Michelsen of the United States.

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

Yosuke Watanuki also surprised by beating No. 35-ranked Brandon Nakashima 7-6 (4), 6-3. The Japanese qualifier next plays seventh-ranked Taylor Fritz of the U.S. or qualifier Terence Atmane of France.