Defending champion John Isner reached another Miami Open final by ending Canadian teenager Felix Auger-Aliassime's historic run.
The 33-year-old American edged out his 18-year-old opponent, who was playing in his first Masters semi-final, in a 7-6 (7-3) 7-6 (7-4) victory.
Auger-Aliassime was left to rue missed chances, failing to serve out at 5-3 in the first set and 5-4 in the second.
Isner fought back to edge both sets and could face Roger Federer in the final.
Switzerland's 20-time Grand Slam champion Federer, 37, takes on Denis Shapovalov - another Canadian teenager - in the other semi-final later on Friday.