As well as the Europa League, Tottenham are also in the FA Cup and have a 1-0 first-leg advantage over Liverpool in the semi-finals of the Carabao Cup.
The win at Hoffenheim means victory for Tottenham at home to Elfsborg next week will likely see them into the knockout stage.
That game comes before a huge couple of days for Spurs as they travel to Liverpool in the EFL Cup on 6 February before going to Aston Villa in the FA Cup fourth round three days later.
Around those they have important league fixtures against Leicester, Brentford and Manchester United as they look to avoid dropping lower than their current 15th place in the Premier League.
“It is a huge couple of weeks for the club,” Hargreaves added.
“It defines their season, with the FA Cup and the second leg of the League Cup.”
Former Tottenham striker Peter Crouch said: “They are one game away from a final.
“They are in the ascendency there. If they get to a final that is a good season.”
Tottenham are now among the favourites to win the Europa League.
With finishing in the top four unlikely, success in Europe’s second-tier competition is their best way of securing Champions League football next season.
“The Europa League they have to prioritise now,” added Crouch.
“I look at the teams and they are capable of beating any of them.”
