Karen Khachanov and Milos Raonic suffered surprise first-round exits at the Dubai Championships on Monday as the event prepared for the return of Roger Federer.

Georgian Nikoloz Basilashvili stunned Russian fourth seed Karen Khachanov 6-4, 6-1, while world number 14 Milos Raonic lost on his Aviation Club debut 6-4, 5-7, 6-4 to German Jan-Lennard Struff.

Federer starts his bid for an eighth Dubai title and the 100th of his career later on Monday against Philipp Kohlschreiber. The 20-time Grand Slam champion is seeded second behind Kei Nishikori.

Federer last played here in 2017, losing in the second round, and claimed his last Dubai title four years ago with a final win over Novak Djokovic.

Khachanov went down in just 69 minutes to 19th-ranked Georgian Basilashvili, winner of two titles last season, as winds played havoc on court.

“I’m quite surprised, for sure,” said Basilashvili. “I know Karen is not having his best time at this moment. But I also did not have great beginning of the season.

“I was able to manage my nerves just (for the) whole match, especially in the windy conditions. It was really tough, (and I’m) really happy for sure.”

Raonic battled for more than two hours but was unable to get past Struff. In an unusual incident, one of Raonic’s rocket serves struck a ball girl straight in face.

After a five-minute pause for treatment, she was led off court by a first-aid worker – the girl returned at the end of the match and shook hands with the player, who gave her a racquet. The Canadian fired 15 aces in his losing effort, dropping serve twice.

Struff advanced into a second-round match with Marton Fucsovics after the Hungarian defeated Damir Dzumhur 6-1, 7-6 (7/5).

Former finalist Fernando Verdasco dealt efficiently with the wind as he put out Italy’s Thomas Fabbiano 3-6, 6-3, 6-2. The Spanish veteran, who lost the 2017 final to Andy Murray, hammered 13 aces in victory. He will face the winner from Federer and Kohlschreiber.

“It was super-difficult, after two hours, I still didn’t know where the wind was going,” said Verdasco. “If the point was long, it was changing during the point.. really, really difficult conditions.”