Memphis - Japanese top seed Kei Nishikori won his second consecutive ATP US Indoor Championships crown on Sunday, beating big-serving Croatian Ivo Karlovic 6-4, 7-6 (7/0) in the final.
It was the fourth career ATP title for the 24-year-old from Shimane, including Delray Beach in 2008, Tokyo in 2012 and last year and this year at the $647 000 Memphis tournament.
"It's an amazing feeling," Nishikori said. "I had never defended a title before."
Nishikori, ranked 16th, took the $103 100 top prize at the first ATP event where he was a top seed and collected his first victory in three career meetings with 80th-ranked Karlovic, who won $54 300.
Nishikori was the first repeat champion at Memphis since Germany's Tommy Haas in 2006 and 2007. The only other was US legend Jimmy Connors.
Karlovic, who fired 56 aces to reach the final without dropping a service game, failed in his bid for a sixth career ATP crown despite blasting 20 aces past Nishikori, who had eight of his own in response.
Nishikori inflicted the only service break of the week against Karlovic in the third game of the first set with a backhand winner, then held twice at love and denied Karlovic's only two break points of the match in the eighth game.
It took four set points in the 10th game before Nishikori claimed the opening set after 41 minutes off back-to-back netted Karlovic backhands.
Karlovic saved two break points in first game of the second set and five more in the third game, denying Nishikori with his 10th, 11th and 12th aces of the match and two service winners as they battled into a tie-breaker.
Nishikori overwhelmed Karlovic in the decider, opening with a forehand winner and a service winner and then watching a forehand from the Croatian sail long.
Nishkori smacked two forehand service return winners for a 5-0 lead and finished matters after 90 minutes on a service winner.
Karlovic, 10 years older than Nishikori at 34 and more than a foot taller at 2.1 metres, had won both prior matches against the Asian star, in last year's first round at Delray Beach and a 2012 Davis Cup meeting.
Nishikori, coached by retired US star Michael Chang, won two singles matches to spark Japan over Canada in Davis Cup play earlier this month and reached the fourth round of the Australian Open, losing to world number one Rafael Nadal.