Middlesbrough relegation 'lowest point' for captain Ben Gibson
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.
Chairman Steve Gibson, who is the uncle of Ben, sacked manager Aitor Karanka in March, with assistant boss Steve Agnew taking the job until the end of the season.
But with just one win in nine league games, the former Barnsley player was unable to guide Boro away from the relegation zone.
"We have to put it right and make sure we come back stronger," said Middlesbrough-born Ben Gibson.
"The chairman and those fans, they deserve Premier League football. People say he's the best chairman in the country and our fans were singing until the end there."
Agnew non-committal on job
Agnew, 51, would not comment on whether he wants to stay with Middlesbrough and try to lead the club straight back to the top flight.
"I have to say the fans all season have been outstanding - home and away has been top class and the least they deserve is Premier League football," he said.
"We need to finish the season strong and reflect through the summer.
"The most important thing at the moment is Middlesbrough football club and we are all bitterly disappointed."
'I felt in my heart I should applaud'
Chelsea manager Antonio Conte, who saw his side move to within three points of winning the title, embraced Agnew at full-time and shook hands with Boro players while also applauding their fans.
"Only in England you can see this support. I've not seen it before," said the Italian, who is managing in his first season in England.
"It's great to see a team fight with all of their strength. They went down and the supporters stayed there.
"This must be an example for other countries. For this reason, I felt in my heart I should go and clap the Boro support."
Analysis - Boro start again with big questions to answer
Former Middlesbrough keeper Mark Schwarzer on Match of the Day
They were very cautious with the players they signed.
Other than Stewart Downing and Brad Guzan there was not enough Premier League experience in those players.
They had momentum as most promoted teams do when they started out in this league but but the momentum wore thin.
It is going to be interesting which direction they decide to go down [with the manager]."
BBC Sport's chief football writer Phil McNulty
Middlesbrough's defiance was confined to their supporters at Stamford Bridge as Steve Agnew's team were outclassed by Premier League champions-elect Chelsea.
Middlesbrough's weakness was an obvious one and was allowed to linger unchecked until it was too late and cost them a place in the Premier League after only one season back in the top flight.
When Middlesbrough went down in 2008-09 they conceded 57 goals. The three here makes 48 for this season with two games left and on many occasions they have looked defensively sound and well organised.
The problem is at the other end, where they have scored only 26 goals - the lowest in the Premier League.
Alvaro Negredo looked a striker past his peak, while Patrick Bamford and Rudy Gestede, brought in from Chelsea and Aston Villa respectively in January, were very poor buys. Middlesbrough paid a heavy price for those transfer misjudgements.
Now they must start again with big questions to answer.
The squad has the appearance of a group in reasonable shape to tackle the Championship, but surely inspirational defender and captain Ben Gibson will be a target for top-tier clubs. And can their magnificent chairman Steve Gibson find it in himself to be a force behind yet another attempt to get back into the top flight?
Middlesbrough is a place with real passion for football and Steve Gibson is the shining symbol of the club, one of the most significant figures in the club's history.
If he can find renewed drive and the right manager then there is still the chance for Boro to bounce back yet again.