Naomi Broady stuns former world No 1 Ana Ivanovic in Auckland

British No 3 Naomi Broady pulled off the biggest victory of her career by stunning world No 16 Ana Ivanovic 7-5 6-4 at the Auckland Open.

The 25-year-old beat the qualifying top seed Magdalena Rybarikova 6-3 1-6 7-6 (8-6) to earn her place in the main draw.

And the world No 122 stunned the former world No 1 - and the second seed in Auckland - with a superb performance to advance to the second round.

It was Broady's first victory over a top 20 player.

Defending champion and top seed Venus Williams suffered a shock 6-7 (4-7) 6-3 6-2 defeat to Russian teenager Daria Kasatkina in the first round.

Kasatkina, 18, ranked No 75 and the third-youngest player inside the top 100, was handed a wildcard in recognition of her undoubted potential.

And she proved the Kiwi organisers right with a stunning win over the world No 7, the American helping her out with an astonishing 73 unforced errors.

After losing the long first set, Kasatkina matched Williams from the baseline and curbed her own errors to take the second.

She then fought back from 3-1 down to win the decider, gaining the vital service break in the seventh game and breaking again in the ninth.

"I couldn't ask for a better start to the year," Kasatkina said. "It took all my power."