"For 45 minutes, we didn't concede one chance to Messi - but of course when we are 2-0 down and you give more space as we are attacking", Pochettino said.
The Barcelona supporters sang his name, the scoreline was shaped by his feet and intelligence and Spurs now find themselves facing a battle to stay in the Champions League.
Harry Kane halved the deficit early in the second half, only to see Messi score at the other end soon afterwards, before Erik Lamela pulled another one back for Spurs on 66 minutes. It's so tough. When you play at this level you can't concede these type of chances.
Keita taken to hospital in Naples following defeat
Although the goal was the obvious highlight of his performance, there was so much more to Insigne's display. The Serie A club were also beaten 3-1 by Juventus in their Serie A clash last weekend.
Barcelona sit top of the group after two wins but Tottenham now face a must-win double header against PSV Eindhoven before hosting Inter and travelling to the Camp Nou.
Tottenham allowed Messi time to curl a pass to Jordi Alba on the left and with goalkeeper Hugo Lloris, back from injury, charging out, Alba cut the ball back to Coutinho, who drilled home through a gaggle of defenders.
Barcelona came into the contest winless in three straight games in their domestic league, this after losing just once in La Liga last season.
Messi put matters to rest just before full-time after a bad giveaway from the Tottenham defence left the Barca talisman alone with only Lloris to beat and he made no mistake, tucking the ball into the bottom right corner to seal the points.
Scholes says Manchester United boss Mourinho is 'embarrassing the club'
United's winless run stretched to four games, following their 0-0 draw with the LaLiga club in the Champions League on Tuesday. On his defenders' performance, the Portuguese said: "They tried, they raised the level of their intensity".
Tottenham's task was made even harder with three core players out injured: Defender Jan Vertonghen, midfielder Dele Alli and playmaker Christian Eriksen, who all featured 11 months ago in a victory over European champion Real Madrid at Wembley.
Ter Stegen came to their rescue on 33 minutes as he stuck out a glove to parry away Lamela's cross that deflected towards goal off Nelson Semedo, while Messi could only pick out Lloris from 14 yards out after combining with Alba as the action quickly switched to the opposite end of the pitch.
'If Moura scores the third goal we talk about heroes and the manager is the best in the world'.
"We had a few problems", Barcelona coach Ernesto Valverde said. The crowd were unbelievable and that's what we need tomorrow night.
The View from Italy: What can Liverpool expect against Carlo Ancelotti's Napoli?
The first difference is up front with Arkadiusz Milik, not Dries Mertens, partnering Lorenzo Insigne in attack . The team scores goals for fun, but unlike under Sarri, they can be got at defensively.