Murray stretches for a forehand in his match against Starace
Andy Murray and Laura Robson lost 2-1 to Italy in the opening group match of their Hopman Cup campaign in Perth.
Robson, 16, went down 7-5 6-3 to 2010 French Open champion Francesca Schiavone after suffering from earache and dizziness in the second set.
Murray needed just 77 minutes to level the tie with a 7-5 6-1 victory over Potito Starace.
But he and Robson were then beaten 6-7 7-6 10-2 by Starace and Schiavone in the deciding mixed doubles.
The British pair now face an uphill task if they are to emulate last year's run to the final.
The US and France complete the line-up in Group B, while Serbia, Belgium, Australia and Kazakhstan are playing in Group A, with the two group winners playing in the final next Saturday.
"It was a very long first day of the year," said Murray, who is gearing up for the Australian Open, starting 17 January.
"It's disappointing we didn't win but hopefully we can come through in the next one."
Robson had been struggling with a cold in the build-up to the match but produced an impressive performance against world number seven Schiavone.
The Briton broke to lead 5-3 in the first set before a run of seven straight games from Schiavone effectively sealed the match.
The first set of Murray's match against world number 47 Starace went with serve before the Scot broke to take it 7-5.
Murray survived an early break point in the second before reeling off five games in a row to take the match.
"I was breathing so hard after the first four or five games," the Scot added. "I only arrived on Saturday afternoon so there's not been a whole lot of time to get over jet-lag yet.
"It's going to take some time to get used to the conditions."
The British duo won the first set of the mixed doubles and led 4-3 in the second, but as Murray tired, the Italians took advantage to level the match before running away with the tie-break.
Murray and Robson reached the final of the Hopman Cup last January, with Murray going on to reach the final of the Australian Open later the same month.
Meanwhile, John Isner beat Nicolas Mahut 6-3 7-6 (7-5) in their first rematch since their 11-hour epic at Wimbledon last year.
Isner beat Mahut to give the USA an insurmountable 2-0 lead over France in a match that lasted 90 minutes - nine and a half hours and 161 games less than their previous record-breaking encounter at SW19 when the American won 6-4 3-6 6-7 (7-9) 7-6 (7-3) 70-68 in the longest match in history.
"If I'd lost that second set it might have gone four hours," said Isner, who later joined Bethanie Mattek-Sands to win the mixed doubles 2-6 6-3 10-8. "But, for the first match of the season, I'm pretty pleased with how I played."