Novak Djokovic’s status as the man to beat in 2019 is indisputable. But when it comes to those other men who have long oppressed their peers in the ATP — Roger Federer, Rafael Nadal, Andy Murray and Stan Wawrinka — things are not as clear. In fact, they’re more murky than they’ve been since the unit known as the Big Four began to dominate major events.

Unless Djokovic runs the table, chances are strong that the Grand Slams will produce a winner outside the usual suspects for the first time since Marin Cilic won the 2014 US Open. There’s been a lot of chatter at the end of the year about the up-and-coming #Nextgen players, led by recent ATP Finals champion Alexander Zverev. But the outsider most likely to crash the Big Four + Stan party probably will be one of three seasoned, tenacious, over-30 veterans.

Two of these contenders have tasted Grand Slam ambrosia in what amounts, at least in tennis-time, to the distant past. Neither has given up on the dream. The three have moved as a group in 2018, inching up to finish ranked Nos. 5, 6 and 7. Most importantly, they are cut from the same cloth; they are big (between 6-foot-6 and 6-8), rangy, powerful and experienced. Let’s take closer look at each of them:

Juan Martin del Potro

Ranking: No. 5
2018 record: 47-13, two titles, including the Indian Wells Masters

It will be five years next September since Cilic cracked the Grand Slam code to win at Flushing Meadows, despite the hegemony of the Big Four. Roughly a year and a half ago, he reached the Wimbledon final, but realizing he had no chance against Federer, Cilic, as the match was coming to a conclusion, sat in his changeover chair with face stained by tears of frustration and anxiety. Cilic did not fare much better this past January when he was thumped in the Aussie Open final, against Federer again.

Paul Annacone, a Tennis Channel analyst who has coached Pete Sampras and Federer, told ESPN.com that Cilic “is the guy none of the big players like to see across the net, not with those weapons, not when he trusts himself.”

The problem has always been that at big moments against top players, Cilic has had a tendency to dial back his game just that wee bit instead of cranking it up. It has made all the difference. “The second serve becomes not quite as big,” Annacone said. “His groundstrokes get a little more erratic.”

Cilic, though, is the most well-rounded of this dangerous trio. He moves extremely well for someone who’s 6-foot-6, and attacks with skill. Cilic’s serve can jar an opponent’s fillings loose. But then, Del Potro and Anderson are equally adept at smoking opponents — or each other. And that just might be what Djokovic and company are hoping they will do, because taking down more than one of the game’s elite in succession at a tournament is pretty much a lost cause.