Watford had taken the lead 39 seconds into the second half through Isaac Success, but Alli and then Erik Lamela struck in the space of four minutes near the end before Etienne Capoue's late effort sent it to penalties, where Alli had the decisive say.

"It is so exciting for him," Pochettino said of Alli. "I gave him the armband because it was so exciting for him to play here in his hometown.

"It is difficult for him to have another possibility to play here again in the future in his career and I wanted to provide him a very good feeling.

"I hope he appreciates a lot my gesture.

"He was inspired by the occasion, to play here he was so excited the energy in the previous day was amazing.

"We can feel here the love that the people feel for him and that was fantastic for us.

"For him it is an experience he will remember for all of his life. To be Tottenham captain and score is a fantastic night for him."

Spurs were playing at the home of Alli's former club as their new stadium is not ready and Wembley was not available.

Over 23,000 fans made the journey 50 miles north for the game and Pochettino was grateful.

"I want to say thank you to our fans, they need to be praised by myself on behalf of the players, the staff to come here and offer their support, they made a massive effort.

"It is important for people to listen from myself, the manager of the club, to that gratitude and then say thank you very much.

"And then to say thank you to all the town of Milton Keynes and all the club, they welcomed us in a very good way. They helped us in every way.

"We'll see what happens with the draw. The objective was to go to the next round, we are so happy of course, it was through penalties but it was fantastic to get the positive result."

Watford's night turned with the decision to award Spurs a penalty with just 10 minutes to go as Christian Kabasele saw red for hauling down Alli.

And boss Javi Gracia, who made 10 changes to his side, could not understand referee Lee Mason's decision.

He said: "I am very proud of my players. I think we played very well and I would like to respect the referee's decision and to support them because I know it is not easy.

"But it is hard to accept, first the penalty and then the red card – I don't understand that decision. I don't understand why the referee showed the red card. I think we will appeal it.

"We tried to the end and competed against a very good Tottenham team, I am proud of my players. I would have liked my players to have the reward because in my opinion they have played very well."

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