London - Novak Djokovic warned his Wimbledon rivals on Sunday that he still hasn't reached his full potential as the world number one bids to move a step closer to a historic calendar Grand Slam.
Djokovic is a strong favourite to win Wimbledon for the fourth time after lifting the trophy at the All England Club for the last two years.
Beating Andy Murray in the French Open final earlier this month brought the Serb the only Grand Slam missing from his collection and if he can retain the Wimbledon and US Open titles he will become the first man since Rod Laver in 1969 to complete a remarkable sweep of the four major prizes in one year.
But, on the eve of his Wimbledon first-round tie against British wildcard James Ward, Djokovic made a revelation about the need to further improve his game that should give his fellow contenders for the title a few sleepless nights.
"Obviously I'm at the peak of my career at the moment. I see still lots of room for improvement, things that I can work on," Djokovic told reporters at Wimbledon.
"That's something that encourages me. That's something that keeps me grounded in a way, gives me more reason to practise.
"I can certainly say I've been working hard to get consistency on all kinds of surfaces."
While Djokovic might see a few imperfections that can be worked on, those flaws have been almost impossible for opponents to detect.
The 29-year-old has won six of the last eight Grand Slams, taking him to a career tally of 12 -- within two of Rafael Nadal's mark and five behind the record 17 of Roger Federer.
Djokovic last failed to reach a Grand Slam final at the 2014 US Open and has reached seven finals, winning six of them, in 2016.
Asked how it would feel to face a player of his calibre, Djokovic reflected the thoughts of the majority of the men's tour when he laughed: "Well, I don't want to go on the other side! (of the net)."
Chasing a calendar Grand Slam proved too much for women's number one Serena Williams to handle last year as she suffered a shock US Open semi-final defeat.
But Djokovic's spirits are so high after finally ending his long wait to win at Roland Garros that he insists the pressure of his history bid won't be a problem.
"Pressure is part of what we do. It's inevitable to face this kind of sensation as a top player," he said.
"But the more you get to face this kind of pressure and emotions, the better you are in coping with it and handling it.
"Of course, the situation this year is quite different from previous years because I'm coming in with a Roland Garros title for the first time.
"That gives me a lot of confidence prior to this event."
Djokovic has beaten Murray in 13 of their last 15 meetings, but he still named the world number two, along with seven-time Wimbledon winner Federer, as his main rivals.
"I would say Andy Murray and Roger because of their rankings, their history of playing well, and winning this tournament, especially Roger for so many times," Djokovic said.
Although Djokovic skipped the Wimbledon warm-up events to wind down after his success in Paris, he is adamant his preparation has been good enough to avoid any early struggles on the grass.
"Winning Roland Garros was obviously one of the most memorable and beautiful moments of my career, but it took a lot out of me. I thought that it's more important for me to just rejuvenate and rest a little bit and then prepare for Wimbledon," he said.
"Even though I've been very blessed to win this tournament three times, I still feel that kind of excitement as though I'm coming in for the first time."