Alexander Zverev battled past Borna Coric in four sets to win an attritional quarter-final at the US Open.
Novak Djokovic's disqualification for hitting a ball at a linesperson has opened up the men's draw at Flushing Meadows and both players at times seemed to carry the weight of that pressure.
Fifth seed Zverev - who had 12 double faults - was particularly slow out of the blocks but as the match wore on was cooler in the big moments en route to triumphing 1-6 7-6 (7-5) 7-6 (7-1) 6-3 and booking a second career slam semi-final having reached the last four of the Australian Open in January.
Zverev, who trailed in the head-to-head 3-1 prior to Tuesday's contest including a US Open defeat to Coric in 2017, faces Pablo Carreno Busta – the beneficiary of Djokovic's indiscretion – or Denis Shapovalov for a spot in the final.
Zverev double faulted three times in a shoddy fourth game, which set the tone for an opening set that produced 12 unforced errors to gift Coric the advantage in just 24 minutes.
The German's composure slipped in game five of the second when a ball was wrongly called out against him and the point replayed, with Coric eventually going on to break after some mammoth rallies and a 20th unforced error of the match from Zverev.
Coric blinked back in game eight, though, and - having initially benefitted from another Zverev double fault - made a crucial unforced error to go 6-4 down in the tie-break and was unable to fight back.
In the third, Zverev had to fight for a crucial hold in game six, before neither man gave an inch in a set in which flashes of quality interspersed conservative tennis.
The breaker went entirely Zverev's way, though, and Coric squandered four break points in game six of the fourth before surrendering serve himself to go down 5-3 when his opponent thumped a forehand winner down the line.
In keeping with the theme of the contest, Zverev was nervy as he served out for the match but found a way to get the job done and became the first German male in a US Open semi-final in 25 years.
Zverev  bt Coric  1-6 7-6 (7-5) 7-6 (7-1) 6-3
Zverev – 52/46
Coric – 37/41
Zverev – 18/12
Coric – 5/2
BREAK POINTS WON
Zverev – 3/8
Coric – 4/15
FIRST SERVE PERCENTAGE
Zverev – 71
Coric – 72
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Zverev – 76/41
Coric – 70/57
Zverev – 136
Coric – 132