Roger Federer's final tuneup event for Wimbledon didn't go as expected. 

Felix Auger Aliassime upset Federer in three sets 4-6, 6-3, 6-2 in the round of 16 at the Noventi Open in Halle, Germany on Wednesday. 

Federer has played sparingly this season as he tries to decrease the amount of stress on his body after undergoing multiple knee surgeries last year. 

After playing just three matches in the first five months, the 39-year-old attempted to win his second French Open and 21st Grand Slam singles title. The Swiss won each of his first three matches at Roland Garros, but a four-set win over Dominik Koepfer that took nearly four hours to complete proved to be more than his body could handle. 

Federer announced prior to a fourth-round match against Matteo Berrettini that he was withdrawing from the French Open.

“I’m just realistic and I know I will not win the French, and whoever thought I would or could win it is wrong," Federer said. 

The Halle Open in Germany will be Federer's final event before heading to the All England Club at the end of the month. He will be looking to win his ninth career Wimbledon singles title. 

The 2021 Wimbledon Championships will start on June 28.