Rafael Nadal lost to Fernando Verdasco in the first round of the Australian Open, an unprecedentedly early exit at Melbourne Park for the 14-time Grand Slam winner and a reversal of their epic, 5-hour, 14-minute semifinal here six years ago.

Fernando Verdasco rallied from a 2-1 deficit to win the last two sets, recovering a break in the fifth as well, and claim a 7-6 (6), 4-6, 3-6, 7-6 (4), 6-2, only his third victory in 17 matches against his fellow Spanish lefthander.

Nadal won his only Australian title in 2009 after beating Verdasco in the semifinals. His only other first-round exit in a major was at Wimbledon in 2013.

Verdasco went for everything on his ground strokes, ripping 90 winners against only 37 for Nadal as he worked to the extremes to unsettle his former No. 1-ranked rival.

"To win against Rafa here coming from two sets down is unbelievable," the 32-year-old, No. 45-ranked Verdasco said. "I think I played unbelievable — the fifth set from the break that he made me, I just started hitting winners. I don't know how, just, you know I was closing the eyes and everything was coming in and I keep doing it and I was doing well."

A winning service return from Verdasco ended the match in 4 hours, 41 minutes.

"Well I think 2009 was maybe the only day in my life that I hit 4, 5 hours," Verdasco said, looking at the clock beside the court to compare it with their semifinal meeting. "It was 35 minutes shorter today — I didn't want to make it longer."

Seven-time major winner Venus Williams also went out in a first-round 6-4, 6-2 loss to Johanna Konta.

The upset results took some focus off the match-fixing allegations that have overshadowed the first two days of the season's first major.

No. 2-ranked Andy Murray began his bid for a drought-breaking title at the Australian Open with a 6-1, 6-2, 6-3 win over Alexander Zverev, checked to see there were no urgent calls from home, and had to answer questions immediately about the reports.

"I just think that it should be tennis that does a better job of explaining ... (players) shouldn't have to read it in the press," Murray said. "You have to be proactive I think with things like this and go and speak to the players rather than them reading about it in the newspapers or listening to it on the TV or the radio."

The BBC and Buzzfeed News published reports Monday alleging match-fixing had gone unchecked in tennis. The reports alleged 16 players, all ranked in the top 50 at some stage and half of them playing at the Australian Open, had repeatedly raised suspicion because of their results and had been flagged with tennis authorities, but had not been sanctioned. No players were identified.

The governing bodies for tennis rejected the claims, and highlighted the fact five players and an official had received life bans after investigations from the Tennis Integrity Unit which was set up in 2008.

Murray, like Roger Federer and Novak Djokovic, thought authorities could be doing more to combat the potential for corruption. Murray also said it was "a little bit hypocritical" for tournaments — including the Australian Open — to be sponsored by betting firms.

Murray has the reached the final four times in Australia but lost every time, including last year to Djokovic. Murray had Amelie Mauresmo, a new mother, back in his coaching corner this week and was happy not to get any mid-match news from home. He has said he'll leave immediately if his wife, Kim, goes into labor in London with their first child.

Venus Williams lost the only final she reached at the Australian Open — to her sister back in 2003 — and her 16th trip to Melbourne Park ended quickly. The 35-year-old Williams had a career comeback last season, winning three titles, finding some consistency after a long struggle with illness and finishing the year in the top 10 for the first time since 2010.

It was the eighth time she's lost in the first round of a Grand Slam tournament and the third time in Australia.

Earlier, No. 3 Garbine Muguruza beat Anett Kontaveit 6-0, 6-4. On the men's side, No. 13 Milos Raonic followed up his win over Roger Federer in the final of the Brisbane International tune-up event with a 6-1, 6-4, 6-4 win over Lucas Pouille.

Joining him the second round will be No. 10 John Isner, No. 18 Feliciano Lopez, No. 23 Gael Monfils, No. 30 Jeremy Chardy, No. 31 Steve Johnson and No. 32 Joao Sousa.