The men's No. 1 seed,
Defending champion Stan Wawrinka, who ended four-time champion Djokovic's 25-match winning streak at Melbourne Park in the quarterfinals last year, advanced to the third round for the seventh consecutive year with a 7-6 (4), 7-6 (4), 6-3 win over No. 194-ranked qualifier Marius Copil.
Williams, seeking a sixth Australian and 19th Grand Slam title, saved three set points in the ninth game before holding to swing the momentum of her match against Zvonareva, a two-time Grand Slam finalist who played only five tournaments in 2014.
Williams said Zvonareva started out really aggressively "and I was a little too passive."
That's when she told herself: " 'You know Serena, you've done so well here, you have nothing to lose' — and I started playing a little better."
After breaking Williams' serve twice in the first set, Zvonareva only won eight points in the second set and didn't get close to another break-point chance.
Venus Williams earned a 6-2, 6-3 win against fellow American Lauren Davis. The elder of the Williams sisters, a seven-time major winner, hasn't been beyond the third round at a major since reaching the fourth round at
No. 24 Garbine Muguruza beat veteran
On the men's side,