Chelsea manager Guus Hiddink was left to rue his side's missed chances as they were beaten 3-2 by Sunderland on Saturday.
Diego Costa and Nemanja Matic scored in the first half to put the visitors 2-1 ahead at the Stadium of Light.
But Costa was twice denied by Vito Mannone after the break and Sunderland fought back to claim a potentially crucial victory in their fight against relegation.
"It was an odd afternoon," Hiddink told Sky Sports. "We started very well and got the lead, but later on we didn't add to our advantage and invited them into it.
"We reacted well to make it 2-1 and in the second half we could have scored to make it 3-1, but we didn't. We invited them into the game and they did very well.
"We didn't score again and they still had the opportunity. For them it was must-win and I cannot blame the attitude of the team, we were a bit sloppy at times, but we came here to win and we didn't do so."
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Chelsea finish their season with a trip to Liverpool in midweek and then a home game against champions Leicester on the final day.
The highest they can finish in the league is ninth, which, although a far cry from winning the league last season, is an improvement from when Hiddink arrived in December with the team struggling in 16th.
"In December we were in the same position as Sunderland," said Hiddink. "It was awkward and we managed in a relatively short time to get out of that area and get into ninth or 10th.
"I would have liked us to further and get some silverware, but it was not the case. We have played for our pride but haven't always got the wins."