Top seed Stefanos Tsitsipas has rallied past a qualifier at the World Tennis Tournament in Rotterdam to reach his first final since the French Open last June.

Tsitsipas ended Czech qualifier Jiri Lehecka’s run 4-6 6-4 6-2 in the semi-finals of the hard-court indoor tournament.

The Greek world No.4 will face Felix Auger-Aliassime in Sunday’s decider of the ATP 500 event after the Canadian third seed came back from a set down to beat defending champion Andrey Rublev 6-7 (5-7) 6-4 6-2.

In the United States, Reilly Opelka won the longest tiebreaker in ATP Tour history to finish off a straight-sets two-hour showdown with fellow American John Isner and advance to the final of the inaugural Dallas Open.

Meanwhile in Buenos Aires, Casper Ruud and Diego Schwartzman progressed to the final of the Argentina Open.

Top seed Ruud eased past local veteran Federico Delbonis 6-3 6-3 while second-seeded Argentine Schwarztman topped third-seeded Lorenzo Sonego of Italy 7-5 3-6 6-2.

In the Netherlands, Tsitsipas was made to work for nearly two hours by the 137th-ranked Lehecka, who previously upset Denis Shapovalov.

Tsitsipas said he did not expect such an aggressive display from Lehecka.

“He was really pushing me,” Tsitsipas said.

“I did not know what to expect, so I was trying to figure out his patterns and his game.

“He was playing incredibly well after the first serve, pressing and attacking like I had never seen before.

“I had to stay in the match and I managed to survive.”

The 20-year-old Lehecka was the lowest-ranked Rotterdam semi-finalist since 1995.

Chasing a maiden ATP title, Auger-Aliassime hit 41 winners, including 11 aces, to snare his first career win over second-seeded Russian Rublev.

In Dallas, second-seeded Opelka sent a winner down the line to secure an incredible 46-point tiebreaker in the second set and seal a 7-6 (9-7) 7-6 (24-22) victory over Isner.

The 24-year-old Opelka now has four straight wins over the 36-year-old Isner. All 10 of the sets he has won against the 16-time ATP Tour title winners have gone to a tiebreaker.

The pair combined for 60 aces on Saturday and have now held 98 straight service games against the other, including 12 straight tiebreakers.