Djokovic, Ferrer, Berdych through in Melbourne

Reigning champion Novak Djokovic looked in ominous form as he eased past Fabio Fognini in straight sets in the Australian Open fourth round. The world number two, seeking his fourth consecutive title in Melbourne, cruised to a 28th straight win on tour with a comprehensive 6-3 6-0 6-2 success over the 15th-seeded Fognini on Sunday. Djokovic served a statement of intent from the off at Rod Laver Arena, holding to love in his first three service games, although he sealed the opener with just a single break. However, the Serb moved through the gears in set two, surging into a 4-0 lead with some sublime play that included a run of taking 14 points from 15 after being taken to deuce in the first game. Overall, Djokovic - whose last defeat came to Rafael Nadal in September's US Open final - broke Fognini's serve six times and struck 33 winners to set up a quarter-final clash with Stanislas Wawrinka. The eighth-seeded Wawrinka, who lost to Djokovic in a five-set epic in the fourth round of last year's Australian Open, overcame Tommy Robredo 6-3 7-6 (7-3) 7-6 (7-5). The Swiss eased to the first set in relatively comfortable fashion, before 17th seed Robredo fought back to force tie-breaks in the second and third. However, Wawrinka - who racked up 14 aces throughout the encounter - held his nerve to secure his spot in the last eight. Earlier on Sunday, third seed David Ferrer battled back from a set down to beat Florian Mayer 6-7 (5-7) 7-5 6-2 6-1. Unseeded German Mayer looked on course to move into a two-set lead when he recovered from 4-0 down in the second to draw level at 5-5 after taking the opener in a tie-break. However, Ferrer - who hit 64 winners, compared to Mayer's 33 - responded by winning 14 of the next 17 games to storm into a meeting with seventh seed Tomas Berdych. Czech Berdych put in a fine display to beat the big-serving Kevin Anderson 6-2 6-2 6-3. Anderson fired down 16 aces during the match, but Berdych did not give up a single break-point opportunity to the 19th seed, while also making just 17 unforced errors in comparison to the South African's 30.