Volkswacht Bodensee - Alcaraz sweats on ankle injury after opening win in Japan

US Open champion Alcaraz crumpled to the ground chasing a shot in the fifth game of the opening set in Tokyo and sat on the court grimacing for several minutes.

The Spaniard had his left ankle heavily strapped during a medical timeout before gingerly returning.

He soon began to move comfortably and broke world number 41 Baez to take a 5-4 lead.

The match was then delayed for a further half an hour as organisers closed the stadium roof with rain falling.

Six-time Grand Slam champion Alcaraz returned strongly and closed out the first set before breezing past Baez in the second.

The Spaniard was unclear afterwards as to the extent of the injury, saying "if it can affect the rest of the tournament, I don't know".

"It's going to be an important day and a half that I have ahead for me before the next match," he said.

"We will see what happens. I will do whatever it takes to be in good shape and ready to play in the next round."

Alcaraz is playing at the Japan Open for the first time and the crowd gave him a warm cheer as he emerged in a burgundy sleeveless outfit.

Their applause soon turned to concern when he went down injured halfway through the first set, with his reaction suggesting he may be unable to continue.

"I was worried because the first minutes of playing, my ankle didn't feel good at all," said Alcaraz.

"But then after all I started to feel a little bit better. I could walk to the bench, which for me was a relief."

Alcaraz faces world number 45 Zizou Bergs of Belgium in the next round on Saturday.

Number two seed Taylor Fritz of the US survived a tough opening test against Canada's Gabriel Diallo to go through 4-6, 6-3, 7-6 (7/3).

Fritz, the world number five, beat Alcaraz at the Laver Cup in San Francisco last week.

"In general, from the two matches I played at the Laver Cup it does give me a lot of confidence," said Fritz.

"I know that I'm playing good tennis but it's not easy to come here, fly that far, jet lag, one day practice then play, switch different court conditions, different balls."

Norway's number four seed Casper Ruud also advanced, with a 4-6, 6-1, 6-1 win over Japan's Shintaro Mochizuki.

Number three seed Holger Rune of Denmark beat Serbia's Hamad Medjedovic 7-6 (9/7), 6-1, but number five Tomas Machac of the Czech Republic went out after losing 6-3, 7-6 (7/4) to Japanese qualifier Sho Shimabukuro.

B.Wyler--VB