Novak Djokovic is two wins away from capturing a 100th career title after beating Sebastian Korda 6-3 7-6(4), in Miami, meanwhile world number one Aryna Sabalenka cruised into her first Miami Open final with a 6-2 6-2 victory over Jasmine Paolini.
Djokovic let out a triumphant roar after sending down an ace on match point as the 37-year-old's former rival and now coach Andy Murray jumped out of his seat to do the same.
The Serbian 24-times Grand Slam champion trailed Korda 5-2 in the second set but broke the American as he served at 5-3 and his precise and powerful serving carried him to the finish.
Victory ensured that Djokovic, who turns 38 in May, became the oldest ATP Masters 1000 semi-finalist, surpassing Roger Federer, who made the final four at Indian Wells and Miami aged 37 years and seven months in 2019.
The match was originally scheduled for Wednesday but postponed under ATP rules aimed at avoiding matches dragging on into the early hours of the morning.
Fourth seed Djokovic, gunning for a record seventh Miami Open title, will face 14th-seeded Bulgarian Grigor Dimitrov in the semi-finals on Friday.
Unseeded Czech Jakub Mensik was a 7-6(5) 6-1 winner over 17th-seeded Frenchman Arthur Fils and will meet American Taylor Fritz in the semis after he outlasted Italian 29th seed Matteo Berrettini 7-5 6-7(7) 7-5.
Third seeded Fritz saw six match points come and go in the second set but converted on his seventh opportunity in the decider to put away Berrettini.
On the women's side, Sabalenka won 77 per cent of her first-serve points, fired down six aces, saved all four break points she faced and converted four of her five break point chances against Italian sixth seed Paolini during the 71-minute match.
The Belarusian top seed, who resides in South Florida and arrived in Miami fresh off a runner-up finish at Indian Wells, has not dropped a set in her five matches.
Up next for Sabalenka will be American fourth seed Jessica Pegula, who ended the fairytale run of Philippine wildcard Alexandra Eala 7-6(3) 5-7 6-3.
Pegula battled back from 2-5 down to win the opening set and was up a break in the second before 19-year-old Eala came back to level the match despite twisting her ankle during a point.
But Pegula's experience shone through in the decider and she prevailed in a thriller that finished well past midnight, with the 31-year-old writing, "I'm tired" on a camera lens.
Eala, who beat three Grand Slam champions during her run, blew kisses to a small crowd that gave her a standing ovation after sharing a warm exchange with Pegula at the net.
Euro 2028 hosts to go through qualifying
Dubai Basketball secures ABA League semi-finals spot
Man City climb to third with 3-1 win over Bournemouth
Ahmedabad to host IPL final on June 3
