The US team of Mattek-Sands and John Isner will meet Belgium, which advanced after Serbia had to withdraw from the tournament because of an injury to Ana Ivanovic.

Ivanovic told a news conference that she will miss next week's Sydney International but hopes to be fit for the Australian Open, which begins Jan. 17.

Isner lost to Andy Murray 6-4, 6-2 in the second singles match on Friday as the No. 4-ranked Briton produced his most assured performance of the week.

The US won the tie 2-1 when Britain forfeited the doubles.

Mattek-Sands' power and consistency proved too much for the 16-year-old Robson, who received treatment for tightness in her right thigh on a day dominated by injuries.

Earlier, Italy's No. 7-ranked Francesca Schiavone had to retire from her match against France's Kristina Mladenovic with a groin problem.

France won the tie 3-0 when Nicolas Mahut beat Potito Starace 6-3, 7-6 (2) and Italy forfeited the doubles because of Schiavone's injury.

That left the US needing to win only one rubber in its tie against already-eliminated Britain and Mattek-Sands delivered it with her third singles win of the week.

After both the day's scheduled doubles matches were canceled, the US took on France in an exhibition set.

Mahut took to the court in a white dress, pink hair band, and knee-length socks, to the delight of the 7,508 spectators.

In Doha, two-time champion Roger Federer reached the final of the Qatar Open by beating third-seeded Jo-Wilfried Tsonga of France 6-3, 7-6 (2) Friday.

Federer, who has yet to drop a set at the Khalifa Tennis Complex this week, could face Rafael Nadal in Sunday's final. The top-ranked Spaniard was to play Nikolay Davydenko later Friday.

"I have played good tennis this week so whoever I play against, I am sure it will be a good match," the 16-time Grand Slam champion said. "I have played two finals here so I have the experience." Federer improved his record to 22-3 in Doha. He won the title in 2005 and '06.

Although the second-seeded Federer was pushed to a tiebreaker in the second set, he said his early first-set break set the tone for the match.

"It was a crucial service break for me. That set me up nicely for the remainder of the match," Federer said.

"The second set was more competitive as I was serving really well." Federer broke Tsonga in the second game of the first set with well-placed returns from the baseline as Tsonga struggled for rhythm. In the tiebreaker, the two were even at 2-all before Federer won the final five points.

"Obviously, I am excited to have reached another final," Federer said. "This sure has been a great week and I am looking forward to my next match."

In Sydney, top-seeded Robin Soderling beat Australian qualifier Matt Ebden 6-3, 6-2 on Friday to advance to the semifinals of the Brisbane International.

The big-serving Swede will face Radek Stepanek, the 2009 Brisbane champion and last year's runner-up, on Saturday.

Stepanek beat Florian Mayer of Germany 6-3, 6-3.

Defending champion Andy Roddick will face Kevin Anderson of South Africa in the other semifinal match.

In the women's tournament, Andrea Petkovic of Germany beat fourth-seeded Marion Bartoli of France 6-4, 6-2 to advance to Saturday's final. She will face Petra Kvitova of the Czech Republic, who defeated Anastasia Pavlyuchenkova of Russia 6-4, 4-6, 6-2.

Stepanek said he felt he was in control against Mayer.

"I was facing a break point, so that was a little bit of an up-and-down game, but I was able to hold my serve and then I had 100 percent control of the whole match," Stepanek said. "I didn't let him come back." The Czech's strong run of results in Brisbane illustrates how much he enjoys the Australian Open warm-up.

"Everything suits me here," Stepanek said. "Since the first tournament in 2009 I've felt on the court here very well. It's always an honor, and when you win a tournament it's obviously a favorite place (and somewhere) you want to go back."

In Chennai, top-seeded Tomas Berdych earned a 6-3, 6-3 victory over Slovenian Blaz Kavcic to advance to the semifinals of the Chennai Open on Friday.

Belgian Xavier Malisse also advanced with a 6-0, 6-2 win over Bjorn Phau of Germany.

Sixth-ranked Berdych broke his 112th-ranked opponent in the fourth game and held on to take the first set. But the Czech had to battle in the second, which featured six breaks.

Berdych, who beat Roger Federer and Novak Djokovic on his way to the Wimbledon final last year, broke his opponent in the opening game and then held serve for a 2-0 lead. Kavcic managed a break of his own before evening the set, but his serve let him down and Berdych wrapped it up.