Defending champion Roger Federer goes for his ninth Wimbledon crown when the year's third major gets underway Monday at the All England Club. The 36-year-old should be fresh after taking off the clay season -- just like he did last year. Sportsbooks list Federer as a +180 favorite, meaning you would win $180 for every $100 risked on Federer adding to his trophy haul. Three-time winner Novak Djokovic (+450), world No. 1 and 2018 French open champ Rafael Nadal (+550), Marin Cilic (+800), Alexander Zverev (+1400) and Juan Martin Del Potro (+1800) lead a strong group of challengers.

Before you make your 2018 Wimbledon picks, you need to hear what renowned British tennis bettor Sean Calvert has to say. The Essex resident lives less than an hour from London and has his finger on the pulse of this tournament.

In 2016 and 2013, Calvert called Andy Murray winning Wimbledon despite Djokovic entering as the favorite. And this year, Calvert called John Isner winning the Miami Open at 100-1 -- a life-changing payout for those who followed Calvert's advice. In March, he nailed Juan Martin Del Porto winning Indian Wells at 10-1.

An unparalleled tennis analyst, Calvert has been cashing huge payouts for six consecutive years. Some of his legendary calls include Stan Wawrinka winning the 2014 Australian Open at 60-1 and Jack Sock winning the 2017 Paris Masters at 80-1. In last year's French Open, Calvert profited a whopping 16 units.

Now, Calvert has analyzed the latest 2018 Wimbledon odds and locked in his bets.

We can tell you Calvert doesn't see Djokovic nabbing his fourth Wimbledon crown. "His grass court stats are excellent and having made the final at Queen's Club last week, he's clearly getting back towards something like his old form, but he's not quite there yet for me," Calvert said.

"The movement is looking much better now, but he's not striking the ball as cleanly and consistently as he once did, plus the confidence can't be anything like as high as it was at his peak," Calvert told SportsLine. "A likely quarter or semifinalist and possible finalist, but I don't see him winning the title this year."

Calvert is highly confident he has the 2018 Wimbledon winner, and he's also backing a monumental long shot to go extremely deep. Anyone who backs this underdog could reap a colossal payday.

Who wins Wimbledon? And what massive long shot stuns the tennis world? Visit SportsLine now to see Sean Calvert's picks, all from the acclaimed expert who called Andy Murray's surprising Wimbledon championship runs and just cashed in huge on John Isner winning the Miami Open at 100-1.