Middlesbrough boss Tony Mowbray admitted he was angry despite his side coming from behind to salvage a 2-2 home draw with Charlton.
Marvin Emnes and Scott McDonald pulled Boro level after Bradley Pritchard and Rhys Williams gave Charlton the lead..
Middlesbrough, early-season promotion contenders, were booed off at the break.
"I can understand the fans' frustrations," said Mowbray. "We built up their expectations in the first half of the season and have let them down.
"And I was angry here. Maybe there wasn't a lot riding on the game for us but I told them it was the last home match and I expected a display.
"It has been a frustrating season but we must learn from it."
Charlton boss Chris Powell added: "I was pleased with the performance if not the result.
"We started off very well and were in a good place and maybe we let it drift a little and that left me a bit frustrated.
"It was a real shame we couldn't convert some of the really good chances we converted."
"I'm pleased with the way the team have performed after coming up a league."