Middlesbrough captain Ben Gibson described his side's relegation from the Premier League as the "lowest point" of his life.
Monday's 3-0 defeat by leaders Chelsea confirmed Boro will go back down to the Championship after one season.
"After the highs of last season, to be honest we've wasted an opportunity to play in the best league in the world," said defender Gibson, 24.
"We have to reflect and try to put it right."
Middlesbrough have been relegated from the Premier League four times, which is the joint highest along with Norwich, Crystal Palace and Sunderland.