Top seed Frances Tiafoe won two matches in a day to progress into the Houston Open semi-finals, while five other seeds bowed out on a busy Saturday of action.

Persistent rain this week in Houston meant the past three days of play have not been completed forcing a massive pile-up of matches on Saturday with the conditions clearing up.

Tiafoe took on Steve Johnson in the morning, winning 6-2 6-4 in the second round, before toppling Australian sixth seed Jason Kubler 6-4 6-4 in the quarter-finals.

The American, who only had a break of two and a half hours between his two matches, said: "I haven’t played two matches in one day in a long time.

"I thought it was unbelievable how I was able to come out here and play so well."

Tiafoe will take on Dutchman Gijs Brouwer in the last four after he got past fourth seed John Isner 6-4 7-6 (7-4), before taking down fifth seed J.J. Wolf 6-3 6-4.

Second seed Tommy Paul was another fancied American to bow out on Saturday, losing 7-6 (8-6) 6-2 to German qualifier Yannick Hanfmann in the second round.

Hanfmann progressed to the semi-finals where he will face Argentinian eighth seed Tomas Martin Etcheverry, with the German getting past Czech qualifier Tomas Machac 6-2 6-1.

Machac had bundled out American seventh seed Marcos Giron 6-4 6-4 in the second round.

Etcheverry progressed with victories over Australia's Max Purcell and Chile's Cristian Garin, winning the latter 6-1 6-7 (2-7) 6-3 in more than two and a half hours.