SAN JOSE, Calif. — On one of the most important points of the match, John Isner walked up to the baseline, bounced the ball between his legs and wasted no time smacking an adrenaline-fueled 138 mph ace.
So long, break point.
So long, set point.
So long, any questions about whether his serve is back.
Isner advanced to the SAP Open semifinals for the first time in his career Friday, rallying in a first-set tiebreaker before overpowering Xavier Malisse 7-6 (8), 6-2 behind his booming serve. The bone bruise in his right knee that forced him to drop out of last month's Australian Open is no longer an issue, and apparently neither is his confidence.
"It's not something I'm going to just try to kick a serve in," Isner said. "I'm going to go for it."
The highest-ranked American saved two break points on his serve in a lengthy first-set tiebreaker, relied on his big-finish forehand for two breaks in the second set and never let his strongest stroke slip during a quick 68-minute match. He will play Saturday against fourth-seeded Tommy Haas, who beat wild-card Steve Johnson 6-4, 6-2.
Isner finished with 10 aces and no double-faults and made 67 percent of his first serves. He improved to 5-2 in his career in San Jose. His previous best finish at the tournament played on a hard court in the home of the NHL's San Jose Sharks had come in 2008, when he lost in the quarterfinals to Guillermo Garcia-Lopez.
After two wins to advance to the semifinals, the remaining field could give Isner tougher competition.
Top seed and two-time defending tournament champion Milos Raonic of Canada had 14 aces in a 7-6 (0), 6-3 win over Uzbekistan's Denis Istomin in the night session. Third-seeded Sam Querrey faced Colombia's Alejandro Falla in the late match.
Neither Isner nor Malisse faced — nor forced — a break point in the first set until the tiebreaker, and Isner never faced one after that. The 6-foot-9 American, ranked No. 16 in the world, kept the rallies short and the time between points even shorter and relied on his serve in the most critical moments of the match.
Malisse took a 3-0 lead in the tiebreaker before Isner smacked a return on the baseline that sent the Belgian backpedaling for a backhand that landed in the net to tie the score 5-all. Both times Malisse earned a set point, he couldn't solve Isner's serve, including a match-high 138 mph ace out wide.
Isner finally flicked a forehand from the baseline at the feet of a charging Malisse on his second set point. Malisse netted the in-between backhand, and Isner pumped his fist all the way to the bench.
The only other drama came three games later, when Isner challenged a called ace by Malisse that was overruled. Isner later went ahead 15-40 and forced another backhand in the net for a break and a 2-1 lead that had the American screaming "Come on!"
Isner earned another break and cruised comfortably on his serve. On match point, he served out wide and put away an easy volley with Malisse well off the court.
At Doha, Qatar, an emotional Serena Williams returned to the top of women's tennis, overcoming a series of potentially career-ending injuries since 2010 to become the oldest woman to hold the No. 1 ranking.
The 31-year-old Williams rallied from 4-1 down in the third to beat former Wimbledon champion Petra Kvitova 3-6, 6-3, 7-5 in the quarterfinals of the Qatar Open. She needed to reach the semifinals to replace Victoria Azarenka at No. 1 when the rankings come out next week.
Chris Evert held the top ranking in 1985 just shy of her 31st birthday.
Williams will face third-ranked Maria Sharapova in the semifinals.
Meanwhile, Azarenka stayed on course to retain her Qatar Open title after dispatching Sara Errani 6-2, 6-2 to also reach the semis. She was joined by Sharapova, who advanced by beating 2011 U.S. Open champion Sam Stosur 6-2, 6-4.
At Rotterdam, Netherlands, Julien Benneteau upset the sluggish Roger Federer 6-3, 7-5 to reach the semifinals of the ABN AMRO World Tennis Tournament.
Defending champion Federer struggled with his serve and the timing of his ground shots throughout the match and Benneteau capitalized, punishing Federer on his second serves, for his second victory over the Swiss master.
The loss ended the top-seeded Federer's bid to become the first player to win the Rotterdam tournament three times.
Earlier, Grigor Dimitrov rallied to overcome Marcos Baghdatis of Cyprus 6-7 (4), 7-6 (0), 6-3 to advance to the semifinals, where he will meet 2009 U.S. Open champion Juan Martin del Potro, who beat Jarkko Nieminen 6-3, 6-4.