Ahead of Friday's two men's semi-finals at Wimbledon, here is a rundown on the two encounters and what to watch for on Centre Court.
Novak Djokovic v Rafael Nadal
It is hard to believe, given how dominant both players have been during their careers, with 29 grand slam titles between them, that Friday's match will be the first time that Djokovic and Nadal have contested a match at Wimbledon since they faced off in the 2011 final.
On that occasion it was Djokovic who prevailed and the Serbian can certainly go on to Centre Court with an optimistic heart on Friday.
The Serbian is playing his best tennis for two years as he appears to have finally put injuries and poor form behind him.
The mental strength, arguably the characteristic that propelled him to world No 1 for the first time in 2011 and kept him at the top of the game for five years is back.
He was superb in coming back from a set down to beat home favourite Kyle Edmund in the third round on Saturday, and then in bouncing back to beat Kei Nishikori in the quarter-finals on Wednesday after dropping the second set.
Djokovic will need all that belief, however, as he has not faced anything yet at Wimbledon of the level of Nadal.
The world No 1 had not made it past the fourth round at Wimbledon since his 2011 final loss, and this run to the last four has been a welcome surprise for fans of the Spaniard.
The 2008 and 2010 champion is competitive on grass again, and anyone with any doubts on his credentials would have lost them after seeing him go toe-to-toe on power with Juan Martin del Potro to defeat the Argentine in five sets on Wednesday.
There are question marks on both men of course. Can Djokovic keep this level up? Can Nadal's body stand up to another tough test less than 48 hours after playing for 12 minutes short of five hours with Del Potro?
Prediction Rafael Nadal to win 3-1.
Djokovic, for all his encouraging form, has only beaten one top 10 player this season, Grigor Dimitrov, and an on-form Nadal is a big step up, with all due respect to Edmund and Nishikori.
Nadal to prevail and move to being within one match of repeating his 2008 and 2010 feats of winning the French Open and Wimbledon titles back-to-back.
Kevin Anderson v John Isner
Opportunity knocks for both men here with a chance at a first Wimbledon final.
Anderson made his breakthrough last September by reaching the US Open final, where he lost to Nadal.
The South African, who won the Mubadala World Tennis Championship in Abu Dhabi in December, had been confident he would carry that form on to 2018.
That did not exactly materalise immediately, as he went out in the first round of the Australian Open, but he had built up a solid season consequently.
The world No 8's victory over Roger Federer was arguably the best result of his career. To come from two sets down, facing a match point in the process, in front of a pro-Federer crowd, and triumph was an excellent achievement.
The pressure is for him to build on it and he faces another player, in Isner, who is in his first grand slam semi-final after coming out on top of his battle of the big servers with Milos Raonic.
Isner's fierce serve has always been a huge weapon, but he has added consistency to the rest of his game.
With Anderson 32 and Isner 33 both men will know they might not have many more chances to reach a major final, which will only add to the pressure of Friday's encounter.
Prediction Kevin Anderson to win 3-0.
This will be another match dominated by serve. Isner's held solid to see off Raonic, while Anderson's withstood a considerable going over from Federer in their clash so both are firing well.
Anderson has a little more to his game at the back of the court, and the consistency and length of his groundstrokes forced Federer in to a number of unforced errors.
Anderson's experience of having already won a grand slam semi-final may also be a factor here.
A brave effort from Isner but it is Anderson who will reach the final.