Japan’s Kei Nishikori captured his third career ATP Tour title on Sunday by routing Spain’s Feliciano Lopez 6-2 6-3 in the final of the US Indoor Tennis Championships.

The fifth seed didn’t drop a set all week and managed to break Lopez’s serve four times in the 67-minute final.

Nishikori, who is ranked 22nd in the world, clinched the win when Lopez sent a backhand wide on the second championship point. Nishikori appeared to injure his elbow on his first match point but managed to serve out the match.

He had three aces, one double fault and won 80 per cent of his second-serve points.

Nishikori, who earned $US290,000 ($A283,000) in prize money, also won a title four months ago on his home soil in Tokyo.

Lopez finished with eight aces, but he also double-faulted three times against Nishikori.

Lopez dropped to 2-6 in title matches with his last win on the tour coming in 2010.