World No.1 Novak Djokovic powered into the semifinals of the Indian Wells ATP tournament with a commanding 6-3, 6-4 victory over Spaniard Nicolas Almagro on Thursday.

The top-seeded Serbian, champion here in 2008 and 2011, will face big-serving John Isner in the last four on Saturday, the 11th-seeded American having edged past Frenchman Gilles Simon 6-3, 1-6, 7-5 in little under two hours.

Djokovic, the hottest player in the sport for more than a year, broke Almagro twice in the opening set and again in the ninth game of the second when the Spaniard hit a backhand long. The Serb then held serve to love in the 10th, an ace putting him 40-0 up before he ended the match with a crunching backhand winner down the line after one hour and 22 minutes.

“It’s definitely satisfying to play well,” Australian Open champion Djokovic said after reaching the last four for a fourth time at Indian Wells. “It was always going to be a tough match. I had a very powerful ball striker on the opposite side of the net. He’s very solid with groundstrokes and has a powerful serve, but I knew that he’s inconsistent with that, so I just needed to hang in there, which I did.”

Djokovic was especially pleased with his serving after firing five aces on the hardcourt surface at the Indian Wells Tennis Garden and winning 73 percent of his second serve points.