The Senegal international has scored three goals in seven appearances after moving to the Blues from the Magpies in a £7m deal earlier in January.
Ba was sensational during his 18 months at Newcastle, scoring an impressive 29 goals in 54 Premier League appearances, before deciding to move to west London.
Rafael Benítez may opt to start Ba as Fernando Torres continues to struggle for goals, and Azpilicueta is confident the new signing will not be affected by a hostile welcome.
“I don’t know how they (Newcastle fans) feel. Demba is a Chelsea player,” said the Chelsea defender.
“He’s going to do his best for Chelsea. It’s true that he played very well there so I think they must be disappointed because he’s a very good player, but he’s going to be focused on the game.”
Meanwhile, Azpilicueta’s compatriot Juan Mata has urged his Chelsea team-mates to cut out the mistakes after the Blues surrendered a two-goal lead at Reading on Wednesday.
“There are no excuses. I don’t know (if the collapse was down to a lack of belief), but it can’t happen again,” said Mata.
“This match was very important because we had an opportunity to be closer to Manchester City and make the gap even bigger to the teams in fourth, fifth and sixth place but we didn’t manage the game way we should have.”
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