Earlier this week, Chilwell underwent surgery on a knee injury and is expected to sit out the rest of the season as he works on his rehabilitation.
The hosts led from the 28th minute until the 90th, but an injury-time header from Danny Welbeck shocked the home crowd.
Danny Welbeck’s last-gasp header in front of the Brighton fans meant Chelsea were left ruing missed opportunities earlier on in the game.
Chelsea will aim to keep pressure on Premier League leaders Manchester City and second placed Liverpool when they host Brighton & Hove Albion at Stamford Bridge on Wednesday.
Chelsea defeated Aston Villa 3-1 in the Premier League fixture on Sunday.
The Blues travel to Aston Villa for a tricky away game in the Premier League this weekend, as they will look to climb up the table.
Chelsea’s reward for the 2-0 victory over Brentford is a two-legged semifinal tie against Tottenham Hotspur in January.
Kante returned to the Chelsea side in the goalless stalemate at Wolves on Sunday and played the full 90 minutes.
Chelsea struggled to get into the game against a spirited Wolves team, who will be disappointed to only take one point.
Tuchel feels that the recent results have not aligned with the quality of the performances - a situation he says is not easy to find solutions to.