Ander Herrera has Manchester United dreaming of FA Cup glory after Mauricio Pochettino's Tottenham again suffered semi-final sorrow.
This was a mouth-watering, season-defining clash for both clubs as a manager driven by silverware faced one driven by progress at Spurs' temporary home.
And it was relentless winner Mourinho who emerged victorious at Wembley, where Alexis Sanchez cancelled out Dele Alli's opener before Herrera secured a 2-1 triumph as Tottenham failed to progress from a record eighth successive FA Cup semi-final.
United will now return to the capital next month for the showpiece finale against Southampton or Chelsea, who Mourinho managed to victory against his current employers in his only previous final appearance in 2006.
The Portuguese could become just the third manager to win the FA Cup with two different clubs, but that possibility looked unlikely when Alli gave Spurs an 11th-minute lead.
Paul Pogba was not alert enough to catch up with Christian Eriksen before he could send in his fine cross but made amends by taking possession off Mousa Dembele and swinging in a fine cross for Sanchez to superbly nod home.
The Chilean's eighth goal in as many Wembley appearances for club and country was followed by Eric Dier hitting the post - but hardworking Herrera would take the headlines.
The Spaniard rifled a low shot past back-up goalkeeper Michel Vorm - a 62nd-minute strike which secured victory in United's record-equalling 29th FA Cup semi-final as Spurs bowed out in the final four for the second successive season.
Pochettino's men wilted after a superb start that was like January's comprehensive 2-0 Wembley win in the Premier League.
It took only 11 seconds to open the scoring that evening. This time it was 11 minutes.
Davinson Sanchez aimed a long, hopeful ball down the right flank, catching Ashley Young horribly out of position and Pogba off guard. Eriksen scampered away, crossing to the far post for Alli to turn in.
Harry Kane was inches away from latching onto Son Heung-min's cross then Eriksen turned wide - but Spurs' boldness in possession turned into over-confidence in the 24th minute as Dembele made the foolhardy decision to try and nutmeg Pogba.
FT: #MUFC 2 Tottenham 1.
Let the celebrations commence! pic.twitter.com/equtgBOM78— Manchester United (@ManUtd) April 21, 2018
The France midfielder stood his ground, shrugged off the Spurs midfielder and sent over a clipped cross which Sanchez headed home superbly.
The belated reaction re-energised United and Jesse Lingard tried his luck as play swung from end-to-end, with underperforming Antonio Valencia picking up a booking for a reckless challenge shortly after Son received a yellow card.
Pogba saw a deflected 25-yard attempt tipped wide by Vorm as half-time approached, before Dier's long-range strike deflected off Chris Smalling and onto the post.
Alli was cautioned for a challenge on Lingard five minutes after the restart and United's attacking midfielder was bemused not to have been awarded a penalty when pushed over by Jan Vertonghen shortly after.
Then in the 62nd minute Lukaku directed onto Sanchez and then fortuitously flicked on the return ball, with Lingard leaving it for Herrera to rifle in.
Spurs were stunned and Lukaku fizzed into the side-netting before being comfortably denied by Vorm.
Eriksen shot just wide as United began to sweat, with Young booked and then Valencia perhaps fortunate not to get another yellow card.
Pogba had an attempt before Dier, substitute Marcus Rashford and Herrera were cautioned as play broke up and United looked to batten down the hatches, which they did successfully.