The elegant surroundings of Queen's Club in west London have served as an ideal grass-court warm-up for many of the great Wimbledon champions over the years and this week a former World Number One has been reminding everyone of the old dictum 'form is temporary but class is permanent.'

Novak Djokovic has endured a dramatic slump in fortunes since lifting his 12th grand slam title at Roland Garros just over two years ago.

However, the 31-year-old three-time Wimbledon champion has shown glimpses in recent weeks of recapturing the form that saw him largely dominate the tour since 2011 until injuries and a loss of form derailed his career after that emotional triumph in Paris in 2016.

His zest for the game certainly seems to have been revitalized and he has been showcasing some seriously impressive form on the immaculate grass courts of Queen's club by strolling to victory in his first two matches, most notably with an emphatic straight-sets destruction of World Number 5 Grigor Dimitrov.

Currently languishing at 22 in the world rankings the Serbian player modestly ruled himself out as a contender for glory at Wimbledon which starts on Monday week.

"Well, I mean, let’s not get, you know, too ahead of ourselves too early," he smiled. "I mean, I had two great matches so far, and I’ll just keep my focus here. I’m definitely not one of the favourites in Wimbledon, so I’ll just try to keep it humble.

When pressed on who he felt were the favourites going into the third grand slam event of the year he predictably nominated the defending champion, Roger Federer and Rafael Nadal fresh off another title on the red clay in Paris.

He did also surprisingly have some encouraging words for Andy Murray who has been off the tour with injury for almost a year until his encouraging return this week ended with defeat to Nick Kyrgios.

He added: "You know, Andy and myself, you know, if we play well. Obviously we dropped in the rankings, but Andy played really well against Nick here first round.

"He has home support and, you know, a lot of things can go in a right direction for him as long as he’s healthy. So, I mean, he’s always tough to play against on grass courts, especially in Wimbledon.

Djokovic's list of the six top contenders extended to last year's beaten finalist Marin Cilic, big serving American Sam Querrey and his vanquished opponent this week, the stylish if somewhat inconsistent Dimitrov.

"Dimitrov, obviously if he plays on a high level, he can really beat anybody this surface. I mean, guys like that, Querrey, Cilic. Of course Cilic, you know."

His final word went to the men with whom he has dominated men's tennis since he emerged as a grand slam champion in Australia in 2008. He gave the favorites tag to eight-time champion Federer but is expecting something special from Nadal who has himself been victorious on the grass at SW19 on two occasions.

"So it’s quite open. I mean, Roger is a clear favourite, without a doubt. Nadal maybe hasn’t played that well in Wimbledon last couple of years up to his standards, but he’s won it several times, played finals several times. He’s definitely rightly one of the candidates to win the title."

Few, however, would rule out a rejuvenated Djokovic from having a major say in the destination of this year's Wimbledon crown.