The world no7 will face either Dominic Thiem or Daniil Medvedev in Sunday’s showpiece at Flushing Meadows after recovering from a hugely disappointing start – and desperate second-set showing – to triumph 3-6, 2-6, 6-3, 6-4, 6-3 in a five-setter inside Arthur Ashe Stadium.
It marks the first time in his career that Zverev has fought back from a two-set deficit to win a match.
The fifth seed is the first German male singles player to reach the US Open final since Michael Stich in 1994.
There initially looked to be very little chance of Zverev – who also made the last four at the Australian Open in January – winning on his second successive appearance in a Grand Slam semi-final, with Carreno Busta looking supremely confident early on and punishing some very sloppy play from the 23-year-old to secure a double break and swift 5-1 lead.
Zverev’s footwork was sorely lacking and he could not find any real semblance of range or rhythm as his opponent successfully closed out the first set at the second time of asking.
He continued to look notably out of sorts and below par in a one-sided second set, with Carreno Busta quickly capitalising on a myriad of unforced errors – including but not limited to rogue forehands and timely double faults – to secure another double break.
The Spaniard, by contrast, was largely error-free in an impressive second set and was striking the ball with crispness and confidence in his second US Open semi-final in four years, racing into a 2-0 lead.
Zverev looked to have a mountain to climb at two sets down and his frustration was evident as Carreno Busta immediately recovered a break at 1-3 in the fourth game of the third set.
However, Zverev then broke again and quickly found some assuredness with his service, producing some extremely comfortable holds to love to reduce the deficit and get on the board.
More to follow