Alcaraz served out the set after the pair came back from the suspension, and took complete control of the second set to win in 90 minutes.
The Spaniard said at first he was seriously worried but felt better as the ankle started to settle.
“I feel like it was unlucky,” Alcaraz said. “I was feeling good and it was about running to a key drop shot he made in the fifth game and that happened.
“I would say it saved me that I was going forward and thanks to that, it didn’t blend all around. I was worried because at the first minutes of playing my ankle, it didn’t feel good at all.
“But then after a while I just started to feel a little bit better. I could walk to the bench, which for me was a relief.
“Right now I’m feeling the same way which for me I would say is great because when it cooled down, I’m feeling the same way when I was playing on the court. I think it’s a great sign.”
Alcaraz was optimistic he could go for his second-round affair against Zizou Bergs of Belgium on Saturday, but would not 100 per cent commit on his availability.
“I don’t know, it’s going to be an important day and a half I have ahead for me before the next match. We will see what happens.
“I will do whatever it takes to be in a good state, and I’m ready to play in the next round.”
AloJapan.com