Andy Murray felt his aggressive treatment of the Roger Federer second serve was the key to his straight-sets win in their Shanghai Masters semi-final.

The Scot, the two-time defending champion, returned superbly as he defeated the world number one 6-4 6-4.

"He didn't serve that well for him tonight, so I was able to be very aggressive on his second serve," Murray, who has now won all 12 matches he has played in Shanghai, said on

The world number three won 64 per cent of points on the Swiss' second serve.

Murray added: "He maybe slowed down his first serve a little bit, so I was able to take a few more chances. Obviously that helped.

"I went for it, like I did the past few times I played against him, and it worked tonight. When you're beating the best player of all time probably, it's obviously going to be special."

Murray held his nerve during a delay while the roof closed because of rain just before he was due to serve for the match.

The Scot will now face Novak Djokovic in the final, the man he beat to win the US Open title last month.

Meanwhile, Djokovic was pleased with his own performance as he swept past Tomas Berdych 6-3 6-4.

"I played tactically right. I was putting a lot of returns into the court, putting a lot of pressure on his serve. On the other hand, I was serving well when I needed to," he said.