Serena Williams suffers shock defeat to Madison Brengle in Auckland

Serena Williams suffered a shock defeat to fellow American Madison Brengle in the second round of the Auckland Classic on Wednesday.

The top seed had been playing in her first tournament since losing in the semi-finals of the US Open four months ago but lost 4-6 7-6 (7-3) 4-6 to the world No 72 in a little over two hours, while her older sister Venus withdrew from the tournament with an arm injury ahead of the second round.

Serena was using the tournament to prepare for the Australian Open and had shown signs of rustiness in her 6-3 6-4 first-round win over Pauline Parmentier before repeated unforced errors against Brengle.

She started with an ace only to follow up with a double fault which exemplified the inconsistent nature of her game in the swirling wind.

Brengle, who had played Williams only once before, losing 6-0 6-1, dropped her second service game but at 4-1 down reeled off five consecutive games to take the first set.

Williams was a set and 4-3 down when she made a comeback of her own, breaking with a delicate drop shot and unleashing a running defensive forehand to clinch the tie-breaker 7-3 and force the decider.

The final set went with serve until Williams double faulted when serving to stay in the match at 4-5.

"Honestly I don't know [how I won]," Brengle said. "It's so cool. It's what you dream about, playing the best in the world. The last time I played her I only won one game, it got a lot better today.

"I just tried to concentrate on every point and run down every ball. It was difficult conditions with the wind and I just tried to fight for every point. I tried to use the slice and get as many balls back as I could and it ended up working out."

On a day of disappointment for the family, Serena's sister Venus beat Jade Lewis 7-6 6-2 but withdrew with a right arm injury.

"I love this tournament and I'm really sad that I have to withdraw, but I'm happy to have had the opportunity to be here again this year," Venus said in a statement ahead of her match against Japanese youngster Naomi Osaka.

British No 3 Naomi Broady also suffered a second round loss in Auckland after being beaten by Julia Goerges 7-5 6-4.

Broady had got off to a good start earlier after beating Danka Kovinic 7-6 6-3 in the first round but went down to the German in straight sets.