Perth:
The United States cruised to victory over France in their Group B tie at the mixed teams Hopman Cup on Monday, as Britain slumped to defeat at the hands of Italy.
The unseeded US pairing of Bethanie Mattek-Sands and John Isner won both singles matches to secure the tie, before completing a clean sweep by claiming the mixed doubles against French duo Kristina Mladenovic and Nicolas Mahut.
The talking point of the clash was the singles rematch between Wimbledon marathon men Isner and Mahut.
In their first on-court meeting since their 11-hour, three-day epic that ended with the American winning 70-68 in the third set in the longest match in tennis history, the pair played for a paltry 90 minutes as Isner sealed the tie for the US.
After Mattek-Sands had overcome a slow start against the teenage Mladenovic to win 3-6, 6-3, 6-1, the 19th-ranked John Isner fired down 17 aces to win in straight sets, 6-3, 7-6 (7/5).
Isner said it was a joy to play Mahut again, the pair bonded forever by their Wimbledon experience.
"It is just a lot of fun playing Nicolas," he said.
"Since that match we have become really, really close friends and it is great to share the court with him."
The Americans won the mixed doubles in the round robin tournament 2-6, 6-3, 10-8 (match tie-break).
Earlier on Monday, heat-stricken Scot Andy Murray dismissed concerns about his health despite struggling through Great Britain's unexpected 2-1 loss to Italy's Potito Starace and Francesca Schiavone in their Group B tie.
The world number four beat Starace in the men's singles 7-5, 6-1 to level the tie after Schiavone beat 16-year-old Laura Robson, herself battling a heavy cold, 7-5, 6-3 in the women's singles.
The Italians then claimed the tie by coming from a set down to win the deciding mixed doubles rubber in a match tiebreak, 6-7 (1/7), 7-6 (8/6), 10-2, with both of the British players appearing to tire late in the match.
Murray admitted he was feeling the effects of his first outings of the year, having arrived in Perth only on Saturday, but said it was nothing to be worried about.
"I'm a bit stiff, which is to be expected after so long travelling and the doubles was very long," he said. "The conditions were tough, but it is normal I think."
Murray said the combination of the oppressive heat and tiredness caused him some problems, but added that it was all valuable preparation for the upcoming Australian Open in Melbourne.
"It's so hot and humid in here -- I was struggling a little bit with my breathing," he said of his singles match.
"I trained outdoors yesterday and maybe overdid it a little bit, but I am trying to acclimatise as quickly as possible."
Meanwhile, Kazakhstan's Yaroslava Shvedova was ruled out of the rest of the tournament with a knee problem and is in doubt for the Australian Open.
Shvedova, ranked 39th in the world, hurt her right knee against Serbia's Ana Ivanovic on Sunday and will be replaced in the Kazakhstan team by 21-year-old Sesil Karatantcheva.
She will see a specialist on Tuesday to determine when she is likely to be back on court.