"We should have got the ball forward rather than played from the back for their first goal".
Substitute Fernando Llorente headed Spurs into dreamland three minutes later, and they will take their three-goal lead back to Germany for the second leg on March 5, a result that already looks beyond doubt unless Spurs stage a dramatic collapse.
Reflecting on the second-half improvement from Spurs, Pochettino said: "The first half was very hard".
'Next time Son scores I will go to the dressing room, have a shower and wait for the game to finish, ' Pochettino joked afterwards.
"The first half was tough, it was an even game but after Sonny scored the team started to feel more free, more confident and started to play in a very good way".
Having started the brighter of the two teams playing at the Wembley, Tottenham Hotspur had been unlucky not to take the lead after seeing a Lucas Moura shot sail wide of the post earlier in the night. They were fantastic. To play after Sunday, with one day less recovery [than Dortmund], we need to praise them.
"Always when you play in this type of competition against a very good side like Dortmund it is hard", said the Argentine. He smiles and he creates energy in every single game. Dortmund did the double over Spurs in the 2015/16 Europa League, while Pochettino's men got revenge last season in the Champions League which included a 3-1 win at Wembley. After a tough first-half, the Belgian laid on Son's goal with a precision cross before banging home a volley of his own.
"3-0 is a very good result but it is only the first leg".
First, it was Sancho, who turned Sanchez inside out with a deft body feint in the first half.
When Vertonghen swung over a cross from the left, Dortmund's defence were out of position for the first time all night and Son timed his run perfectly behind Zagadou to caress a fine volley past Roman Burki. I am very happy for him, he deserved it.