Despite a few glitches along the way, including 39 unforced errors to just 23 winners, Federer looked extremely focused as he improved his round-robin record to 1-1 in the season-ending tournament that features the top eight men's singles players.

Davydenko fell to 0-2 and was virtually eliminated, barring injuries to players above the Russian in the Red Group.

Fifth-ranked Andy Roddick faced No. 7 Fernando Gonzalez later. Both won their opening matches, with Gonzalez upsetting Federer. It was Federer's second consecutive loss, the first time in 4 1/2 years he had lost twice in a row.

Swiss flags were draped around the indoor stadium and painted on the faces of several Chinese women in the crowd that was clearly pro-Federer.

Both players began well, with the first break opportunity not coming until Davydenko served at 3-4. Federer, going for winners but sometimes missing badly, quickly converted and served for the set only to see Davydenko break back. But Davydenko's errors handed the set to Federer when he doubled-faulted at deuce, then missed a forehand wide.

Federer cut his mistakes in the second set and had Davydenko in constant trouble. He squandered four break points with Davydenko serving at 0-1 in a game that went to deuce six times, then ran off four games in a row to take command at 5-1. Davydenko got back one break as Federer served for the match and held to pull within 5-3.

But Federer was just too good in the end, shouting "Yes!" in clear relief when Davydenko committed his 26th unforced error on match point. Playing mostly from the baseline, the Russian just didn't have enough to hurt Federer, compiling only 11 winners.