Miami Open: Serena Williams struggles

Serena Williams, of the United States, celebrates after defeating Christina McHale, also of the United States, 6-3, 5-7, 6-2, during a match at the Miami Open tennis tournament. (Photo: AP)

World number one Serena Williams was forced to regroup but launched her bid for a ninth Miami Open crown on Thursday by defeating US compatriot Christina McHale 6-3, 5-7, 6-2.

Three-time defending champion Williams had the match on her racquet before having to withstand a fightback from her 23-year-old rival and taking two hours and seven minutes to reach the third round.

Top seed Williams, who watched tournaments at the combined WTA and ATP hardcourt event as a child, will next face Zarina Diyas of Kazakhstan, who ousted Australian Daria Gavrilova 7-5, 6-3.

Two-time Wimbledon winner Petra Kvitova reached the third round with a 6-1, 6-4 victory over 83rd-ranked American Irina Falconi.

Kvitova next faces Russian 30th seed Ekaterina Makarova, who ousted Ukraine’s Lesia Tsurenko 3-6, 6-4, 6-3.

British wildcard Heather Watson ousted US 20th seed Sloane Stephens 6-3, 6-0. She faces Belgium’s Yanina Wickmayer in the third round.

Denis Istomin rallied to beat Borna Coric 4-6, 7-5, 7-5 to book a Saturday matchup with British second seed Andy Murray, who won their only two matches back in 2013.

Fifth seed Rafael Nadal face Bosnian Damir Dzumhur, who rallied past Leonardo Mayer 4-6, 6-3, 6-4.

Japanese sixth seed Kei Nishikori plays his second-round match against Pierre-Hugues Herbert, who downed Lukas Rosol 7-5, 6-4.