Sinner, Alcaraz face off in Beijing

Jannik Sinner ignored the bubbling controversy over his steroid case and a roaring home crowd to set up a China Open final against Carlos Alcaraz on Tuesday.

The world number one and defending champion defeated the 96th-ranked Chinese wildcard Bu Yunchaokete 6-3, 7-6 (7/3) to avoid a major upset.

The Italian faces Spanish second seed Alcaraz, who was in fine form in a 7-5, 6-3 victory over Russian third seed Daniil Medvedev in the other semi-final.

"It's a very delicate moment, very difficult, very different," Sinner said after racking up a 15th win in a row even as he makes headlines off the court.

"So every victory for me is a great sign."

In front of a packed house on China's national day, US Open champion Sinner was facing a player he had never met before and who was competing in the biggest match of his life.

China's 22-year-old Bu was also in the form of his life, having reached the semi-finals last week in Hangzhou.

Bu had Sinner under pressure on the Italian's serve early in the first set, but Sinner staved off the threat and the storm gradually blew itself out as the set wore on.

They went to the tiebreak in the second set, with Sinner sending down his 11th ace of the contest to convert his third match point.

Nobody has won more matches on tour this season than Sinner, 23, who failed two doping tests in March but was cleared of wrongdoing and allowed to keep playing.

Tennis authorities accepted Sinner's explanation that trace amounts of a steroid unintentionally entered his system from a physiotherapist who used a spray containing it to treat a cut, then provided massage and sports therapy to the player.

The World Anti-Doping Agency (WADA) reignited the case on Saturday, saying it had appealed against the decision and is seeking a ban of up to two years.

Sinner has admitted to having sleepless nights over the issue.

Four-time Grand Slam champion Alcaraz reached his first Beijing final and is in ominous form, yet to drop a set.

"I felt great on the court once again, so I'm really happy about it. I think I couldn't ask for a better semi-final," said Alcaraz, who is chasing a 16th ATP Tour title -- which would equal Sinner.

The two have met nine times previously on the tour, with the Spaniard holding a 5-4 edge, but Sinner won their semi-final in Beijing last year.