Chelsea lost further ground in their battle to make the Premier League top four as they were held to a 1-1 draw by a stubborn Nottingham Forest side.
Raheem Sterling put Chelsea ahead at Forest's City Ground in the 16th minute, before Serge Aurier drew the teams level with an acrobatic finish in the 63rd minute.
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A mistimed header from Pierre-Emerick Aubameyang late on was as close as Graham Potter's side got to a winner, but the visitors could not force a way through. They are now seven points behind Manchester United in fourth place.
"I think overall when the game was controlled in the first half I don't think we did well enough, our performance level wasn't good enough, didn't move the ball fast enough," Potter said.
"They use their advantages which is the environment, the crowd. The second half we didn't control it well enough."
Forest had an early chance in the 10th minute when Brennan Johnson was sent through on goal by Morgan Gibbs-White, but Kepa Arrizabalaga got down well to stop the initial shot and the follow-up.
But Chelsea took the lead when Sterling took full advantage after a bizarre attempted clearance from Willy Boly bounced off the bar.
The hosts pushed forward after the break, with Johnson forcing Kepa into another save in the 50th minute before Gibbs-White produced a brilliant shot which thundered off the bar and to safety.
Forest finally found the breakthrough when Aurier steered a volley past Kepa after Chelsea failed to clear a corner, with the right-back celebrating the equaliser wildly.
Aubameyang then failed to connect with a fizzing Hakim Ziyech cross as Chelsea searched for a second goal, but Potter's side fell short.