Reilly Opelka defeated his childhood hero John Isner to win the tallest final in ATP Tour history at the US Clay Court Championship in Houston on Sunday.

The 24-year-old Opelka powered past the veteran Isner in straight sets to claim the fourth singles title of his career with a 6-3, 7-6 (9/7) victory.

Sunday's showdown between the two towering Americans -- Opelka stands at 6ft 11in (2.1m), with Isner at 6ft 10in -- was billed as the tallest ATP Tour final of the open era.

It also marked a symbolic moment for Opelka, who grew up watching the 36-year-old Isner.

"He was my idol growing up as a kid, and before I even met him, I liked him," Opelka said after his win.

"But since then we've become such good friends and spent so much time on Tour, I like him even more now," Opelka added.

"He's been an unbelievable role model for not just myself, (but) Taylor Fritz, Frances Tiafoe and Tommy Paul. We all say the same. He's been an unbelievable competitor for a long time."

Sunday's win extends Opelka's record of dominance against Isner, with Opelka leading 5-1 in head-to-head meetings between the two.

"We've played a handful of times and you keep on beating me. I hate you for that!" Isner quipped at Opelka after the final. "But it was cool to play you in a final."