Arsenal boss Mikel Arteta, speaking to BT Sport: "You never get used to winning. I knew the challenge we faced today against this incredible opponent. Thank you very much to the players for the effort and performance.
"The courage of the team, how aggressive we were without the ball and against the Liverpool press. I am pleased and knew in the second half we would suffer. But in the penalties we had courage to do them right.
"In the last 10 minutes we took the ball and played in the final third. I am pleased how they competed. It creates belief."
Arsenal player ratings
David Luiz: 7
Tierney: 7 (Kolasinac 83)
Bellerín: 6.5 (Cédric Soares 59)
Saka: 7 (Willock 82)
Nketiah: 6.5 (Nelson 82)