Canadian Milos Raonic is all about quick starts.

Raonic earned a clinical, 6-1, 6-4, 6-4 first-round win over Lucas Pouille on Monday at the Australian Open. The 25-year-old from Thornhill, Ont., has learned that his greatest strength is when he breaks out in an early lead.

"Playing ahead is always a little bit easier," said Raonic. "The main thing you have to be on top of yourself for at that point is not have any letups. I think I stayed ahead pretty much on my service games. Other than maybe a Love-15 once, I think I was ahead the whole time.

"I don't think it got to deuce ever. I was putting myself in good spots."

The win over Pouille followed up Raonic's victory at the Brisbane International.

Raonic, who at No. 13 has his lowest seeding at a Grand Slam tournament since Wimbledon 2013, is aiming to improve on his run to the quarter-finals here last year, when he lost to eventual champion Novak Djokovic.

"In Brisbane I also had quite a few opportunities. Maybe today, just having a bit more comfort and understanding of where I was playing, maybe I let down on a few games when it came to returning," said Raonic. "But I did a good job taking care of my serve and I was proficient on the return games when I needed to be.

Nadal stunned by countryman

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

Verdasco rallied from a 2-1 deficit to win the last two sets, recovering a break in the fifth as well, claiming 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.

Australian Open Tennis

Rafael Nadal of Spain wraps ice towels around his face during a break in his first round match against Fernando Verdasco, which he would go on to lose. (Aaron Favila/The Associated Press)

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 when he lost in straight sets to No. 135-ranked Steve Darcis of Belgium.

"It's a hard and painful loss," the fifth-seeded Nadal said.

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 four hours, 41 minutes.

"Well I think 2009 was maybe the only day in my life that I hit four, five 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."

Big upsets on women's side

There were two big upsets in the women's draw, with No. 2 Simona Halep and seven-time Grand Slam winner Venus Williams losing in the first round.

Halep, the 2014 French Open finalist, lost 6-4, 6-3 to Zhang Shuai for her third first-round loss at Melbourne Park in the past five years, but giving the No. 133-ranked Chinese qualifier her first win at a Grand Slam after 14 losses.

"It's OK. I don't want to make this match like dramatic," said Halep, who refused to blame an Achilles tendon problem that forced her out of a warmup event for her earlier loss.

After beating Halep, Zhang burst into tears when asked about breaking the drought.

"I think in my life, it's the best tennis," she said. "To win against a top-two player, I'm so happy, so excited."

Williams lost 6-4, 6-2 to Johanna Konta, her eighth first-round loss at a major.

No. 3 Garbine Muguruza and No. 7 Angelique Kerber advanced along with two-time Australian Open champion Victoria Azerenka, who closed play on centre court with a 6-0, 6-0 rout of Alison Van Uytvanck.

Wawrinka, Murray move on

Stan Wawrinka, who beat Nadal in the 2014 Australian final, and four-time runner-up Andy Murray advanced, along with Lleyton Hewitt, the two-time major winner who is playing his 20th and last Australian Open tournament before retiring.

French Open champion Wawrinka was leading 7-6 (2), 6-3 when his opponent Dmitry Tursonov retired with what appeared to be an upper leg injury.

No. 2-ranked Murray opened with a 6-1, 6-2, 6-3 win over Alexander Zverev, who checked to see there were no urgent calls from home — his wife is expecting their first child next month.

Among the other men advancing were No. 8 David Ferrer, No. 10 John Isner and No. 18 Feliciano Lopez.

With files from The Associated Press