PERTH, Australia (AP):

Feeling lethargic and jet-lagged, Serena Williams decided a coffee might perk her up after losing her first set 6-0 at the Hopman Cup.

It did the trick.

Williams recovered to beat Flavia Pennetta 0-6, 6-3, 6-0 on a sweltering day in Perth, John Isner followed up with a 5-7, 7-5, 7-6 (4) win over Fabio Fognini and the American pair combined to win the doubles for a 3-0 win over Italy in Group A on Monday in the international mixed team competition.

Williams later joked it was "miracle coffee."

The top-ranked Williams laughed loudly as she checked with the chair umpire and then with the tournament referee about the coffee before a ball girl served her the brew on court.

"I was just feeling it, so I just had to get some coffee into me," Williams said. "I just asked them to get me a shot of espresso - I asked them if it was legal, because I've never done it before. I needed to wake up."

Williams, the 18-time major winner, said the round-robin nature of the Hopman Cup took some pressure off her ahead of the Australian Open later this month.