Frank Lampard criticised Chelsea for failing to see off Brighton and Hove Albion before half-time on New Year's Day, as Alireza Jahanbakhsh's sensational late strike earned a 1-1 draw.
The Blues led early through Cesar Azpilicueta and were then comfortable for the most part until they came under increasing pressure in the final 10 minutes.
Kepa Arrizabalaga was forced into impressive saves either side of a stunning overhead-kick from Jahanbakhsh.
Chelsea also could have clinched the points in the closing minutes, yet Lampard did not believe they should have been in a position where the game was still in the balance.
"It was frustrating for different reasons," he told BT Sport. "In the first half, the game was there to be won.
"We weren't ruthless enough. We got the goal and we had the possession. But we just didn't kill the game off. We allowed them to stay in the game.
"In the end, it was a wonder goal. But we were lucky not to lose the game. In the end, the tactics matched up for both teams. But they were better than us. We have to take that on the chin."
Jahanbakhsh had not appeared in the Premier League this season until December and, despite joining Brighton in 2018, only scored his first goal for the club against Bournemouth on Saturday.
A second strike in quick succession brought the Iran winger further delight, as he reflected on "a very tough time".
"It's obviously a great feeling to be involved in such important games," Jahanbakhsh said. "I've been working hard to get my chance.
"I was finally there last game and tried to help the team and make an impact. It had been a long time that I didn't play, but I'm very happy to help the team and make the people happy.
"It's been a very tough time for me, but I'm very glad I've turned it around. It's been two great games, and I'm really happy to help the team to get points."