When the wiry former MK Dons star crashed into a thunderous challenge with Morgan Schneiderlin in the middle of the Wembley pitch, strode forward with long leggy steps, collected the ball back from Wayne Rooney and smashed it into the top corner of the French goal, there was a genuine sense of deja vu.
This tall, agile all-action midfielder had announced himself, that was his moment.
Not only does he love a tackle, but clearly he has an eye for the spectacular too.
The cameo felt all too familiar, and that's because it was so reminiscent of Liverpool great Steven Gerrard it was uncanny.
And it wasn't just the tackle and goal. The way Alli was gliding across the Wembley turf full of confidence brought back memories of that exciting young Liverpudlian first breaking into the Liverpool side back in 1998.
Marauding about the pitch putting in tackles, sneering at opposition players calling for free-kicks after feeling the unlikely force of one of his challenges.
As Reds fans try to adjust to life after one of their greatest ever players, along comes a midfielder so eerily similar.
What is even more sickening for the Anfield faithful is the fact he could have been theirs too. Alli was a boyhood Reds fan but at £5 million was considered too much of a risk for Liverpool, as reported by Sky Sports.
Liverpool will not be the only ones kicking themselves, though.
What must MK Dons be thinking, after that goal and his performances for Spurs, what would he be worth now?
My reckoning is a lot more than £5 million.
There will be bumps along the way, of that there is no doubt, but Alli really does look the real deal.
One thing is for sure, if he goes on to have half the career Gerrard did, both he and Tottenham will be more than happy.