Top seed Daniil Medvedev crashed out of the Rotterdam Open on Wednesday, losing to 104th-ranked Canadian Vasek Pospisil who marched into the last 16 with a 6-4 6-3 victory.

World No.5 Medvedev, long-touted as one of the most likely of the new generation of players to win a grand slam, saw his Rotterdam challenge ended in just 68 minutes by Pospisil.

The 29-year-old Canadian, who continues a fine run of form having reached the final at the Open Sud de France in Montpellier last week, managed to save five of six break points while converting three of his own en route to a huge upset.

France’s Gael Monfils started his Rotterdam title defence with a convincing 6-3 6-2 victory over Portugal’s Joao Sousa.

Monfils who beat Pospisil in the final to win in Montpellier last week, needed only 70 minutes to dispatch his Portuguese opponent, firing five aces and converting four break points.

The 33-year-old Frenchman, who is looking to become the first player to win back-to-back Rotterdam titles since Sweden’s Robin Soderling in 2011, next faces compatriot Gilles Simon who beat Mikhail Kukushkin 7-6 (7-3) 3-6 6-3.

“It’s never easy to come back after a win,” Monfils said. “But I have great memories from last year.”

In an all-Spanish showdown, Pablo Carreno Busta beat sixth seed Roberto Bautista Agut 6-4 2-6 7-6 (7-4) to qualify for the quarter-finals after a battle lasting nearly two-and-a-half hours.

Carreno Busta fired 11 aces and saved seven break points to advance at his higher-ranked compatriot’s expense.

Belgian fourth seed David Goffin battled back from a set down and saved two break points in the decider to beat local hope Robin Haase 3-6 7-6 (7-5) 6-4.

Goffin will face Italian Jannik Sinner, who was awarded a walkover after his opponent Radu Albot withdrew.