Perth, Dec 31 (IANS) Former world No. 1 Serena Williams on Monday earned a solitary victory for the United States against Greece in the Group B women's match at the Hopman Cup tennis tournament held here.

Williams prevailed 7-6 (7-3), 6-2 over 23-year-old Maria Sakkari after one hour and 44 minutes, collecting 13 aces and forcing her Greek opponent to commit 10 double faults, reports Efe news.

Meanwhile, Greece's rising star Stefanos Tsitsipas, 20, battled a 6-3, 6-7 (3-7), 6-3 win over the US' Francis Tiafoe in the men's duel that lasted two hours and 15 minutes.

The Greek pair, Sakkari and Tsitsipas, defeated the US Williams and Tiafoe duo 4-1, 1-4, 4-2 in the mixed double encounter, after just 53 minutes, securing a 2-1 advantage for the European team.

--IANS gau/sed