Steve Johnson will defend his title against Tennys Sandgren at the US Men's Clay Court Championships after overcoming Taylor Fritz in the semi-finals.

Johnson reached back-to-back finals in Houston thanks to Saturday's 7-5 6-7 (4-7) 6-2 win against fellow American Fritz.

The defending champion and sixth seed was tested by Fritz but he outlasted his countryman after two hours, 22 minutes on clay.

Johnson, who converted four of 15 break points after eliminating top seed John Isner in the quarter-finals, is bidding to become the first player since Andy Roddick in 2001-02 to win consecutive Houston crowns.

It will be an all-American decider after Australian Open quarter-finalist Sandgren trumped Ivo Karlovic 7-6 (7-2) 7-6 (7-4) for his first ATP World Tour final.

Sandgren – the eighth seed – survived an onslaught from big-serving Croatian Karlovic, who tallied 35 winners and 10 aces.