Alexander Zverev's campaign at the National Bank Open in Montreal ended after the World No 3 lost 7-6, 2-6, 4-6 to Tallon Griekspoor in the second round on Wednesday.
The defeat marked Griekspoor's third career victory over a top-five opponent and sent the Dutchman into the third round of the ATP Masters 1000 tournament.
Zverev entered the tournament as the No 1 seed after several leading players, including world No 1 Jannik Sinner and Novak Djokovic, withdrew from the event.
As one of the top 32 seeds, the German received a first-round bye and opened his campaign directly in the second round against Griekspoor, who had already played and won his opening match.
The opening set was closely contested, with neither player able to establish a decisive advantage. Both held serve throughout the set before it was decided in a tie-break. Zverev produced the stronger performance in the breaker, taking it 7-3 to move ahead by one set.
Griekspoor responded strongly in the second set. The Dutchman raised his level from the baseline and capitalized on his opportunities against the Zverev serve. He secured two breaks and won the set 6-2 to level the match after just over an hour of play.
The deciding set remained competitive during the early games, with both players holding serve.
Griekspoor eventually earned the crucial break late in the match and maintained his advantage to complete a 6-4 victory. After converting a match point, the world No 69 sealed one of the biggest wins of his season and advanced to the third round in Montreal.
Tallon Griekspoor speaks on his win
Griekspoor termed the win over Zverev as one of the most special wins in his career. "This is one of the most special [wins] I have had," he said in his interview on the court after the match.
"I have had a very tough season, which is not easy. I have been very close to throwing the towel a couple of times. But I have been working harder and harder lately and reached quite a good level in training in the past couple of weeks. I felt like it was just a matter of time. This one is special, especially against a player like Sascha," he added.
The Dutch player said the victory wouldn’t have been possible without his coaching staff members. This was only his third win over the German, who still leads the head-to-head meetings between the two (9-3).
"If you know the history I have had with him, I have thrown away a couple of breaks I have had in the third or fifth, so I have wasted a couple of opportunities I have had against him," he said. "Without the guys in the box, I probably would have lost this one. They kept me there, stayed with me and helped me through," he added.
