Djokovic will face either Federer or David Goffin in Sunday's final, live on Sky Sports Arena from 9pm, after a 6-4, 3-6 6-3 victory over world No 7 Cilic that showcased all the form and qualities of his dominance between 2011 and that landmark moment in Paris.
The 10th-seeded Serbian first finished his rain-delayed third-round match against fifth-seeded Bulgarian Grigor Dimitrov, a 2-6, 6-3, 6-4 triumph, before ousting Canadian Milos Raonic 7-5, 4-6, 6-3 in 2 hours, 29 minutes in the quarterfinals. After dropping the first three games of the final set, she took a medical timeout for treatment.
One point away from another loss, she had pulled off her biggest win, one that left her as stunned as everyone else.
Djokovic, meanwhile, outlasted Marin Cilic to reach the final, where he will bid to complete the set of all nine Masters 1000 titles.
With both players near their consistent best, Wawrinka saved two break points in the sixth game, while Federer offered his compatriot none.
"Obviously the match against Dimitrov yesterday didn't start so well for me".
"If I fight like I've done here, I will have a big chance", Halep said.
She's expecting a lot of attention at the U.S. Open, where she reached the final past year and lost to Sloane Stephens - her best showing in a Grand Slam event. "It was a different kind of serve because I was serving differently because of the speed of my ball, and it would have been tough to win".
The 10th-seeded Serb squared the match as the day's second bout of major rain moved in. She became the first unseeded player to win in Cincinnati since Vera Zvonareva in 2006. "I must be very pleased with fighting spirit and staying mentally tough to overcome deficits in both matches".
It will mark the first time since Gstaad in 2004 that Federer has played two matches on the same day.
"After I lost the first set, I had to serve two more sets to win the match, so it didn't make sense to continue".
Women's top seed Simona Halep recovered from 1-4 down in the opening set, reversing her losing momentum to defeat Lesia Tsurenko 6-4, 6-1. "To see where I was also few weeks ago, I'm really happy to be here", he added.
His record in OH is mixed, having won all five previous semi-finals, he has gone on to lose all five finals that he has reached, three of those against Federer whom he could line up against on Sunday evening.
Raonic would break Djokovic's serve early in the second set and coast through his service games en route to taking the second set by a score of 6-4.