World number one Carlos Alcaraz is through to the semi-finals of the Swiss Indoors Basel after easing past Pablo Carreno-Busta in straight sets.

Alcaraz took just under an hour and 40 minutes to overcome his fellow Spaniard and friend 6-3 6-4, getting 67 per cent of his first serves in and winning 77 per cent of those.

Carreno-Busta struggled to keep the US Open champion at bay, facing 12 break points in all, and although he saved nine of them, his defiance was ultimately in vain.

"It is difficult to play against a friend like Pablo," Alcaraz said on-court after his win on Friday. "Every day we go and have dinner, lunch, together. Every week and we train together, so it is difficult to play against him.

"I also support him and want him to win every match. On court, there are no friends. You have to be focused and go for the match and that is what I did."

Alcaraz will face third seed Felix Auger-Aliassime in the final four after the Canadian defeated Alexander Bublik 6-2 6-3.

The other semi-final will see Roberto Bautista Agut play Holger Rune after the Spaniard beat Stan Wawrinka 7-5 7-6 (7-5) and the Danish teenager defeated Arthur Rinderknech 7-6 (7-0) 6-2.

In Austria, top seed at the Vienna Open Daniil Medvedev beat Jannik Sinner 6-4 6-2 to advance to the last four, where he will play Grigor Dimitrov after the Bulgarian overcame Marcos Giron 6-3 4-6 6-4.

The winner of that contest will face either Denis Shapovalov, who beat Dan Evans 6-3 6-3, or Borna Coric after the Croatian came through against Hubert Hurkacz 6-4 6-7 (2-7) 7-6 (7-5).