Life-long Blues fan Gardner helped the club gain a shock victory over Arsenal in the final at Wembley.
But the Blues midfielder knows the euphoria of that occasion will be forgotten if the club return to the Championship for next season.
"We've won a trophy but, if you go down, it counts for nothing," said Gardner.
"If you win a trophy and stay up, it's probably one of the best seasons you're going to have in football.
"We need to make sure we do that and keep fighting and we've got the right characters here.
"You can see the fire in the eyes of everyone in the dressing room.
"The lads want it and the gaffer (Alex McLeish) wants it."
Source: PA
Source: PA