Zappacosta marked his first Chelsea start, and also his debut game at Stamford Bridge, with a superb strike after he won the ball on the right flank, raced forward and then delivered a powerful effort that hurtled into the far corner of the net.
When asked whether he thought Zappacosta meant to cross the ball instead of score a goal, Azpilicueta told the London Evening Standard: "I think so.
"But more than this, he got the ball from the wing, he dribbled well and he tried to cross - and it was a perfect shot.
"I'm happy for him. It was his first game at Stamford Bridge and to get that goal, for his confidence, it's great."