John Isner was stunned by Daniel Evans in the semi-finals of the ATP Delray Beach Open, while Felix Auger-Aliassime's dream week continued at the Rio Open.

Isner looked to be on track for a spot in the final after winning the first set but the American second seed crashed to a 3-6 6-2 6-2 defeat on Saturday.

The path to victory in Delray Beach opened up for Isner following the surprise elimination of top seed Juan Martin del Potro in the quarter-finals.

However, Isner – who had not been broken in 77 service games dating back to his opening-round defeat to Reilly Opelka at the Australia Open – lost his way.

Evans reeled off three successive breaks in the second set to swing the momentum in his favour and the Englishman did not look back at the ATP 250 tournament.

He will now have the chance to claim his maiden tour title when he faces Radu Albot, who outlasted Mackenzie McDonald 3-6 6-0 6-0.

Meanwhile, Canadian teenager Auger-Aliassime reached the Rio Open decider courtesy of a 6-3 3-6 6-3 victory against Pablo Cuevas.

Auger-Aliassime, who had not advanced to a tour semi-final prior to the event in Rio de Janeiro, became the youngest ATP 500 finalist since the level was established in 2009.

Serbia's Laslo Djere awaits in the final after Aljaz Bedene withdrew from the semis due to a right leg injury.