The Dutchman, who led United to their first silverware since 2016 when they won the League Cup in February, warned his team not ease up in their bid to earn a place in Europe's elite club competition.
United are fourth in the Premier League, seven points ahead of fifth-placed Liverpool who have played a game more.
Ten Hag's team have six league games left, starting with Thursday's trip to Brighton & Hove Albion, before facing Manchester City in the FA Cup final.
"Satisfaction can lead to laziness, we have six games to go and we want to win every game. You need full focus, full energy and full preparation," Ten Hag told reporters.
"We have to get ready for the fight to get the points. We want to win every game; we want to win every competition. It's clear we want to be in the Champions League, and that's the competition we're now fighting for.
"Good isn't good enough; we have to do better."
United beat Brighton on penalties in the FA Cup semi-finals last month, and Ten Hag acknowledged that Roberto De Zerbi's men would be fired up by the thought of revenge.
"They have a huge motivation to beat us but we have to match that and do more, show more hunger than them to win this game and willingness is the word for tomorrow," Ten Hag said.
Young forward Alejandro Garnacho is still nursing an ankle injury but is back in training while defender Raphael Varane and midfielder Scott McTominay will be unavailable for at least two more games.
