The Arsenal defender came on for Ben White, and with his first touch, he headed in the opener - his first goal in more than two years.
After a goalless first half, Chambers was introduced in the 55th minute and the 26-year-old broke the deadlock with his first touch of the game.
Arsenal and Chelsea defeated Leeds United and Southampton respectively on Tuesday to advance to the quarterfinals of the competition.
Pierre-Emerick Aubameyang scored a crucial goal in the convincing 3-1 victory over Aston Villa in the Premier League on Friday night.
The Portuguese full-back started on the left side of a back four for Arsenal and enjoyed a dream outing against Aston Villa on Friday night.
Arsenal were at their ruthless best on Friday night, beating Aston Villa 3-1, thanks to goals from Thomas Partey, Pierre-Emerick Aubameyang and Emile Smith Rowe.
Arsenal beat Aston Villa 3-1 in the Premier League fixture at Emirates stadium on Friday.
Lacazette came from the bench and scored a crucial late equaliser in the thrilling 2-2 draw against Crystal Palace in the Premier League.
Arsenal salvaged a late draw against Crystal Palace thanks to Alexandre Lacazette’s injury-time strike in the Premier League clash.
Arsenal and Crystal Palace played out a thrilling 2-2 draw at Emirates in the Monday night Premier League fixture.