Novak Djokovic has declared Wimbledon "pretty much an open field" despite his near-absolute dominance of men's tennis over the last 12 months.
As holder of all four grand slam titles, Djokovic sets out to achieve what no male player in the Open era has managed, namely to win five in a row.
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Since the majors began allowing professionals to compete, from 1968, Australian Rod Laver's four in a row - a calendar sweep of the board in 1969 - stood alone as the men's record until this year.
Djokovic joined him on four straight by landing his first French Open at the start of June, but the world number one expects a tough title defence at Wimbledon.
"You always have the top players, the ones that were most dominant on the grand slams in the previous years that are always in contention for winning the trophy ? Andy Murray, Roger (Federer) ? first of all, because of their rankings, their history of playing, playing well, and winning this tournament, especially Roger for so many times," Djokovic said.
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"Then you have Milos Raonic, who has been playing very well. He has a big serve, which is an obvious advantage on this surface that is quickest we have in sports."
Canadian Raonic now also has John McEnroe on his coaching team at Wimbledon, on an apparently one-off basis.
The list of contenders according to Djokovic does not stop there.
"You know, (Nick) Kyrgios is definitely one of the players that can go far," he added.
"I think it's pretty much an open field. But I think the beauty of all the grand slams and of this sport is that you always start from scratch and you always start from the same starting position as everybody else, fighting for the trophy equally as everybody else."
Djokovic gets his campaign under way against Britain's James Ward on Centre Court at 1pm on Monday.
While Ward will be playing perhaps the biggest match of his life, for Djokovic such occasions are almost routine.
It makes them no less special, as the 29-year-old Serbian reflected on the eve of the tournament.
"There is a corridor from the men's seeds' locker room all the way to the entrance of the Centre Court, probably the most special corridor we have in sports," Djokovic said. "You get to have that sense of belonging to history, something that is much larger than yourself.
"Being just part of it and observing everything as you go along, as you approach one of the most important tennis stadiums and courts in the world, your excitement is growing, and tension, many different emotions.
"I was fortunate to experience that more than a few times. When you are walking towards the Centre Court prior to the finals, it's quite different than any other match, obviously.
"Especially in the last two years, I can recall playing against Roger in the finals, thrilling finals both.
"Managing to win the trophy that I always dreamed of winning, sharing it obviously with my family, the team, the people closest in my life, it's truly a blessing.
"Whenever I would come back, I would relive those memories. That would stick in my mind. So I'm trying to always be aware of it. That gives me even more motivation."
Seven-time champion Federer, after missing the French Open through injury, starts his campaign against Argentinian Guido Pella, third on Centre.