The game got off to a tough start for Chelsea, with goalkeeper Robert Sanchez receiving a red card just five minutes in for a reckless tackle on Bryan Mbeumo.
Manchester United's Bruno Fernandes scored the first goal in the 10th minute, and Casemiro added a second in the 37th minute.
Despite a late goal from Chalobah, United's lead held, and they won the game 2-1.
In a candid post-match interview, Chalobah acknowledged that the team's performance was not good enough.
"We need to take responsibility as players," Chalobah said. "Our performance in the first 15 minutes was the worst this season. We should reflect on that as a team and learn from it."
Chalobah also pointed out that the team's young age is no longer an excuse, given their experience in the Premier League.
"Any team would struggle to come back from 2-0 down, especially after going down to 10 men," Chalobah said. "We were under pressure from United, and we couldn't get started in the first half."
Chalobah emphasized the importance of learning from this experience and moving forward.
"Things like this happen in the season. We're not kids anymore. We've played in the Premier League long enough to know how to handle situations like this."