INDIAN WELLS, United States - Japan's Kei Nishikori, the highest ranked Asian player in ATP Tour history, opened his Indian Wells campaign with a 6-4, 6-4 win over Ryan Harrison on Saturday.
The US Open runner-up broke Harrison five times to reach the third round of the WTA and ATP Masters hardcourt tournament.
"There were so many ups and downs in the first set. I broke him many times and that was the key for today's match," Nishikori said.
The 25-year-old Nishikori, who is ranked fifth in the world, advanced to the third round, where he will play Fernando Verdasco of Spain.
Nishikori came into Indian Wells having won last month in Memphis after reaching the quarter-finals at the Australian Open.
He also reached the finals in Acapulco and has reached the quarters in all four tournaments he has competed in this year.
It was the second match in a short period of time and just the second career ATP meeting between the two. Nishikori beat Harrison in three sets 3-6, 6-3, 6-4 in Memphis.
Saturday's second round match was equally entertaining.
Neither player was able to take command in the first set, combining for seven breaks of serve. Nishikori would eventually convert on his third set point.
He secured a break to open the second set and then clinched the victory on his second match point when Harrison hit a shot long.
"Luckily I got the first break, so it was easier mentally to hit a lot of good shots," said Nishikori, who was ranked as high as fourth in the world earlier this month. "But I'm really happy to win today with how I performed in the second set, and I'm looking forward to playing in the next round." Fourth seed Andy Murray needed just 80 minutes dispatch Canada's Vasek Pospisil 6-1, 6-3 and reach the third round.
The Scot broke Pospisil five times to claim his 13th win of the season.
The fourth seeded Scot had lost twice previously in his opening Indian Wells match in 2011 and 2012, but had little trouble taking care of Pospisil.
Reigning US Open champ Marin Cilic crashed out of the Indian Wells event Saturday after losing his first match of the 2015 season 6-4, 6-4 to Juan Monaco of Argentina.
Cilic, who is ranked 10th in the world, has been sidelined with a right shoulder injury.
"It's getting there," Cilic said of the shoulder. "I didn't feel completely painless. I felt that it's a bit rusty still.
"Even on my serve I wasn't able to hit it at a full speed. So that gave him a little more opportunities and more freedom in the game." Flavia Pennetta opened the defence of her WTA title by beating American Madison Brengle 6-4, 6-2 in second round action.
Pennetta, who turned 33 last month, clinched the victory with a crosscourt forehand winner in a match that lasted 75 minutes.
Last year, Italy's Pennetta dominated Poland's Agnieszka Radwanska 6-2, 6-1 to win the biggest title of her career in the California desert.
The world number 16 said she was nervous about launching her title defence.
"This morning I woke up and I was shaking a little bit. During the match I was trying to be focussed on what to do and not be rushed," she said.
In other women's matches involving seeded players, fifth seeded Serb Ana Ivanovic defeated Yulia Putintseva 6-3, 6-1 and fourth seeded Caroline Wozniacki of Denmark eased past Ons Jebeur 7-6 (7/3), 6-4.