Milos Raonic successful in return to the court in St. Petersburg, Russia

The last time tennis fans saw top Canadian Milos Raonic, his back was spasming during a painful loss to Spain's Feliciano Lopez in the third round of the US Open.

The loss wrapped up a difficult summer, during which the 24-year-old struggled with ancillary physical issues in the wake of his foot surgery in the spring, particularly his back.

Raonic returned Thursday in St. Petersburg, Russia, in the indoor conditions he has had so much success on during his career. And he had no trouble in dismissing Russian wild card Evgeny Donskoy 6-4, 6-4 to move into the quarter-finals against Tommy Robredo of Spain.

It took just an hour and 12 minutes.

"It’s a start. To be able to succeed at this tournament, you have to win the first one," Raonic said in an on-court interview.

Tournaments with 28-player fields are challenging for the top four seeds, who have first-round byes. As the No. 2 seed, Raonic had been in St. Petersburg all week waiting to play, not having signed up for doubles. He didn't step on the court for an official match until late Thursday, and will have to play four consecutive days if he aspires to the title.

He did, however, hit the Hermitage with just the hint of a 'stache.

The Rebound Ace court (a surface made of used tires that was used for years at the Australian Open until they finally realized the extreme summer heat there melted it) is a good one for Raonic. It slows down the ball enough to allow him to catch up with it, but it emphasizes spin – which makes his kick serve all the more effective.

Raonic used both his kick serve and his power serve - his first two deliveries of the match checked in at 223 and 222 km/hour – to great effect. Donskoy saved two break points in the first game of the match but was unable to hold on at 4-4, when Raonic's crafty slice backhand handcuffed Donskoy at the net and gave him the break.

He lost his first point of the set on his first serve as he tried to close it out, but wrapped it up with a 230 km/hour unreturnable bomb and an ace.

The second set was even more routine. Raonic broke in the first game with a backhand down-the-line winner. And if he didn't convert the break opportunities he had in Donskoy's next two service games, the early break was more than enough.

He served it out this way: 191 km/hour ace out wide in the deuce court. 220 km/hour ace out wide in the ad court. 232 km/hour second serve, and 227 km/hour second serve.

In all, Raonic had 13 aces and no double faults, saved the only break point he faced, and lost just nine points total on his serve.

He even was successful on a couple of Hawkeye challenges, and managed to avoid being distracted by the huge contingent of cheerleaders that populated the centre court.

"I didn’t look up. I tried to focus," Raonic said in his on-court interview.

Raonic's compatriot, Vasek Pospisil, didn't fare as well at the other ATP Tour event in Metz, France.

After defeating Aleksandr Nedovyesov of Kazakhstan 6-1, 7-5 in the first round, Pospisil fell to No. 6 seed Martin Klizan of Slovakia 6-4, 7-6 (7) in the second round on Thursday.

Pospisil out-aced Klizan, a 26-year-old lefty ranked No. 35, 12 to six. He won more points (73 to 72). But in the end, he couldn't pull it out in a tight tiebreak.