Men's World No. 1 Novak Djokovic made a winning start to his sixth Wimbledon and record-equaling 20th Grand Slam bid Monday as Wimbledon returned at a soggy All England Club.

Djokovic also saw a potential semifinal opponent and French Open runner-up Stefanos Tsitsipas crash out against Frances Tiafoe.

One year after the 2020 tournament was canceled due to the coronavirus pandemic, defending champion Djokovic claimed a 4-6, 6-1, 6-2, 6-2 win over Britain's 253rd-ranked Jack Draper.

Third seed Tsitsipas, however, beaten by Djokovic in the French Open final just two weeks ago, slumped to his third first-round defeat in four visits to the tournament.

America's Frances Tiafoe, ranked 57, stunned the Greek star 6-4, 6-4, 6-3.

Andy Murray, the 2013 and 2016 champion, won his first Wimbledon singles match since 2017 with a 6-4, 6-3, 5-7, 6-3 victory over the 24th seeded Nikoloz Basilashvili of Georgia.

They were amongst a handful of standout moments as heavy rain brought chaos to the opening day with just 32 of the scheduled 64 matches completed.

Djokovic, 34, struggled on the slippery Centre Court surface with the roof closed due to the rain which had delayed play on outside courts for five hours.

Left-handed Draper, playing just his fifth match on the main tour, saved seven of seven breakpoints in the opener to stun the top seed.

But Djokovic soon snuffed out any danger of him becoming only the third defending champion to lose in the first round, by sweeping through the remainder of the tie.

He finished with an impressive 25 aces and 47 winners as his 19-year-old opponent, who grew up just 9 kilometers (6 miles) from the All England Club, wilted.

"I probably had one of the best serving performances that I can recall on any surface," said Djokovic.

He next faces Kevin Anderson, the South African he defeated in the 2018 final.

'It sounds good'

With the Australian and French Open titles under his belt, the Serb is bidding to become only the third man in history to claim a calendar Grand Slam.

His match was preceded by a standing ovation for professor Sarah Gilbert, one of the key scientists behind the Oxford AstraZeneca COVID-19 vaccine who was a special guest in the Royal Box.

Tiafoe won a second-tier grass-court Challenger event in Nottingham this month before making the quarterfinals at Queen's Club.

On Monday, he made that match hardness pay against Tsitsipas, playing only his 16th match on grass.

It was the first time in 12 attempts that 23-year-old Tiafoe had beaten a player ranked in the top five.

"It sounds pretty damn good," said Tiafoe.

Tsitsipas, weary of life in the tennis bubble, admitted it had been a struggle.

"There have been times that I was much more motivated than this. But that's no reason for me not to play well," he said.

Now ranked a lowly 118 in the world, former number one Murray won his first singles match at the All England Club since 2017 when he lost to Sam Querrey in the quarterfinals.

A long-standing hip problem, which required surgery, then pushed him tearfully to the brink of retirement.

"I keep on being asked will it be my last match or my last Wimbledon," he said Monday.

"I don't know why I keep on being asked. I want to keep on playing. I enjoy it and I can still play at the highest level."

Wimbledon looks very different this year with COVID-19 protocols in place and a 50% capacity until finals day, but one familiar feature was the summer rain.

Play on the outside courts started so late that 32 of the day's scheduled 64 matches will have to be completed on Tuesday.

The Belarus second seed Aryna Sabalenka had the honor of being the first winner at the tournament in two years when she downed Romanian qualifier Monica Niculescu 6-1, 6-4 under the roof of Court One.

Former U.S. Open champion Sloane Stephens knocked out Czech 10th seed Petra Kvitova, the 2011 and 2014 champion, 6-3, 6-4.

Garbine Muguruza, the 2017 winner, needed just under an hour to see off France's Fiona Ferro 6-0, 6-1.

Hotel bubble

Players are confined to a hotel 'bubble' in central London this year.

However, there have already been two virus-related withdrawals – Britain's Johanna Konta and former men's doubles champion Frederik Nielsen, both identified as close contacts.

"This is not unexpected," said All England Club chief executive Sally Bolton.