California - World number one Novak Djokovic powered into the semi-finals of the Indian Wells ATP tournament with a commanding 6-3 6-4 victory over Spaniard Nicolas Almagro on Thursday.
The top-seeded Serb, champion here in 2008 and last year, 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 a 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, 22 minutes.
"It's definitely satisfying to play well," Australian Open champion Djokovic told reporters 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 ground strokes 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.
"I served well," said the Serb, who has won four of the last five grand slams to establish himself as the sport's top player.
"I didn't lose many points on my service games in both sets and that's something I have been working on. I have been trying to get more free points on the first serves. This hasn't been my weapon in the past."
Djokovic and the 12th-seeded Almagro pounded the ball ferociously from the baseline to create several lengthy rallies which, more often than not, ended in the Serb's favour.
"I have played so many matches on the tour and on the big stage in major events, and I learned over the years what I need to do in order to play my best when it matters the most," Djokovic added.
"I use that necessary experience to perform my best, to cope with pressure and just understand what shots I need to play at a certain time, even though sometimes you don't need to go for winners."
Djokovic, who outlasted Spaniard Rafa Nadal 5-7 6-4 6-2 6-7 7-5 in an epic final at the Australian Open in January, improved his win-loss record this season to 14-1 by reaching his third straight semi-final.
Isner and Simon, both playing in the quarter-finals for the first time at Indian Wells, traded the first two sets in their evening match and the third then went with serve until Simon was broken in the 12th game.
A deep forehand service return by Isner forced a baseline error from Simon and the American converted the first of his two match points when Simon hit a backhand long.
"It's my first match on this court this year and the ball was flying out there," the 6ft 9in (2.05m) Isner said in a courtside interview after blasting 11 aces. "It was a bit difficult for both of us to adjust.
"I'm very happy to get through. I didn't get too frustrated. A lot of times, I felt like I could hit forehand winners but I made a lot of mistakes. He does that to a lot of players. I stayed focused and I pulled it out."
In the remaining quarter-finals on Friday, three-times champion Roger Federer was scheduled to play Juan Martin del Potro of Argentina before twice winner Rafa Nadal of Spain faces Argentina's David Nalbandian.