SHANGHAI, Nov 14: World No 1 Roger Federer got his Masters Cup campaign back on track by eliminating Russia’s Nikolay Davydenko in straight sets on Wednesday.

The triple Masters Cup champion, shocked in his opening match by Fernando Gonzalez, overwhelmed the Russian 6-4, 6-3 in one hour and 27 minutes to stay in the running for his sixth straight semi-final.

Later, Andy Roddick became the first man to book his place in the last four as he hammered Gonzalez 6-1, 6-4.

Federer was expected to come out firing after losing to Gonzalez, but he made a pedestrian start before pouncing in the eighth game, converting his first break point as Davydenko put a backhand volley long.

The Swiss, who sprayed an eyebrow-raising 39 unforced errors, suffered an unaccustomed wobble when serving for the set and swiped a baseline backhand into the net to be broken back.

However, Davydenko’s revival proved short-lived as Federer, recovering his aggression, broke again for the set as the Russian miscued with a forehand volley.

Federer converted the last of five break points at 2-1 in the second to put a stranglehold on the match, roaring with delight as he finally found form.

Davydenko’s volley failed him yet again as Federer broke for 5-1. But the Swiss was again broken when serving for the set, and the match, before finally finishing it 6-3 on Davydenko’s misfired backhand.

The result means Davydenko, appearing at his third straight Masters Cup, cannot reach the semi-finals following his straight-sets loss to Roddick.

For Federer, also beaten in Paris by David Nalbandian, it ended a run of two straight defeats, his first since 2003. He had never lost in 15 round robin matches at the season finale until Monday.

The 26-year-old triumphed in 2003, 2004 and 2006, with his only previous defeats coming in the 2002 semis to Lleyton Hewitt and in the 2005 final to David Nalbandian.

In the later match Gonzalez, Federer’s latest conqueror, looked exhausted by his heroics as he failed to hold serve until 5-0 down in the opening set against a whirlwind Roddick.

The Chilean, in turns frustrated and befuddled as he hit a ball into the stands and collided with a line judge, put a backhand long to gift the American the crucial break for 2-1 in the second set before Roddick served it out on one hour and six minutes.

Wednesday’s results (prefix number denotes seeding)

Red Group: 5-Andy Roddick (US) bt 7-Fernando Gonzalez (CHL) 6-1, 6-4; 1-Roger Federer (SWI) bt 4-Nikolay Davydenko (RUS) 6-4, 6-3.—Agencies