Federer into last four before beating Roddick

SHANGHAI (Reuters) - Roger Federer's place in the semi-finals of the season-ending Masters Cup was decided before he had even hit a ball in anger on Friday.

The world number one then destroyed Andy Roddick 6-4 6-2, triggering a couple of furious outbursts from the American who smashed one of his rackets to pieces and at one point shouted over the net: "Don't worry, I'll get better!"

Russian Nikolay Davydenko's 6-4 6-3 victory over Chile's Fernando Gonzalez was enough to send Federer through regardless of the result of his final Red Group match.

Federer, chasing his fourth Masters Cup title in five years, now faces world number two Rafael Nadal in Saturday's semi-finals of the showcase eight-man event.

"Let's not over-rate today's match -- we'd both qualified," Federer told reporters. I'm excited to play Rafa. I think if I'm on top of my game indoors I'm the favorite."

Federer has regularly tormented Roddick in their past meetings and his 14-1 head-to-head record was never under threat in a one-sided match.

The Swiss breezed through the first set in 33 minutes, clinching it with a sharp forehand volley to leave his opponent in a hole.

SIZZLING FOREHAND

Things got even worse for Roddick as Federer broke twice in the second, putting the American out of his misery after just 61 minutes with another sizzling crosscourt forehand.

Federer had little sympathy for Roddick.

"He gives off an attitude sometimes of being very disappointed," said Federer. "So sometimes you're like 'Okay, sorry I hit that passing shot'. But at the same times that's tennis and he knows it."

Roddick must now pick himself up for Saturday's first semi-final with Gold Group winner David Ferrer after being put to the sword by Federer.

Such was his frustration, Roddick reduced one racket to a mangled heap, smashing it repeatedly against his heel after going down a double break in the second set.

"When you're down 6-4 4-0 you're not adoring your chances," shrugged Roddick. "It seems like most times we play he's on top of his game, which is a little annoying."

(Editing by Clare Fallon)