WELLINGTON (REUTERS) - Top seed Serena Williams was made to work hard against fellow American Christina McHale before she prevailed 3-6, 6-2, 6-3 to advance to the quarter-finals of the Auckland Classic on Thursday (Jan 9).

The 23-time Grand Slam champion looked a completely different player from the person who smashed her way into the semi-finals of the doubles with Caroline Wozniacki on Wednesday but managed to do just enough to beat the 86th-ranked McHale.

McHale, who had not beaten Williams in their three previous matches, kept her compatriot off balance with clever use of angled returns and chased down everything the 38-year-old hammered back at her.

Williams only seized control of the match in the fifth game of the decider when she broke the 27-year-old before she wrapped up the win in two hours.

She will now face Germany's Laura Siegemund, who upset American teenager Coco Gauff 5-7, 6-2, 6-3 in a 2hr 14min match that opened Thursday's action on the main court at the Auckland Tennis Centre.