On Thursday night, Spurs succumbed to a 3-0 defeat in Germany in a fixture where they were overpowered and outclassed by their opponents, and it appears that they face an impossible task to overturn the deficit when the two teams meet in the second leg at White Hart Lane next week.
Pochettino has been criticised in some quarters for his decision to rest the likes of Harry Kane and Erik Lamela, but Cascarino has insisted that it was the correct decision.
The former Chelsea forward feels that Pochettino is right to prioritise the Premier League, with the club currently five points adrift of leaders Leicester City and with a game against bottom side Aston Villa to come on Sunday.
Cascarino said: "He did the right thing. They lost the game and people might look at that they have missed a great chance to win a trophy, but not with the Premier League on the horizon.
"They have a chance. This club hasn't won the top flight for 50-odd years and given the position that they are in, I think that he has to say that we must have our best XI in a Premier League game.
"If they win at Villa Park at the weekend, which they are quite capable of doing, that will say it all about whether he was right or wrong because the Premier League has to be their primary target."
Some supporters on social media also questioned why Pochettino rested players in a competition where they had fought hard to reach the last 16, but Spurs haven't always been in contention at the top of the domestic standings.
They have capitalised on the poor form of North London rivals Arsenal and Manchester City, and at one stage, the Europa League arguably represented their best chance of securing a place in next season's Champions League.