Roger Federer
Roger Federer returns a shot from Vasek Pospisil in the second round of the Cincinnati Masters.Reuters

Swiss maestro Roger Federer has added yet another milestone to his long list of achievements by claiming his 300th Masters level win in Cincinnati against Canada's Vasek Pospisil.

Federer reached this special milestone 14 years after registering his first ATP 1000 victory over American Justin Gimelstob in the Miami Masters.

The former world number one would have notched this special feat in Rogers Cup, but Frenchman Jo-Wilfried Tsonga extended the wait for few days by beating the Swiss in the final.

"The Masters 1000s are the backbone of the tour," said Federer. "I know a lot of people talk about the Grand Slams; we care dearly about them, but the majority of the tournaments are Masters 1000s, 500s or 250s.

"We have a certain obligation to play the 1000s, and I think that's why they're so popular, that's why the people show up because they know that the best players will most likely play.

"I have a few exempts because I've been on tour for a very long time so I don't have to always play, but I choose to because they're very prestigious and I love playing them, so I'm happy I'm here."

Federer had to dig deep to claim a 7-6 (4), 5-7, 6-2 victory over Pospisil to book a clash with Frenchman Gael Monfils, who registered an easy 6-4, 6-1 win over Roberto Bautista Agut in just 59 minutes.

Federer, a five-time Cincinnati champion, won a tight opening set in the tiebreaker, but the Canadian forced the decider by taking the second.

Pospisil, however, failed to maintain the second set momentum in the third, as the world number three raced to a 5-1 lead and won the match in just over two hours.

Meanwhile, former Wimbledon champion Andy Murray faced no difficulties in dispatching Portugal's Joao Sousa 6-3, 6-3 to enter the last 16. The Scot played with much better control than his last outing in the Toronto Masters.

Murray, who is aiming to reach his first final since his Wimbledon triumph last year, converted three break points and also saved a couple of breaks on his serve.

"I hit the ball well from the back of the court today," Murray said. "I was able to control the ball well. That was, for me, the most pleasing thing about the match today, because I have seen a lot of the players have struggled so far."

In the Round of 16, Murray will face last year's finalist John Isner, who fired 16 aces and defeated Australian qualifier Marinko Matosevic in straight sets.