The Argentina international joined from Aston Villa on a three-year contract and was immediately handed a starting spot at Stamford Bridge.
Martinez produced several sharp reaction saves to help the Londoners secure all three points.
Alonso was delighted with his new goalkeeper’s immediate impact and believes Martinez’s experience and personality will prove valuable throughout the campaign.
“Emi is a World Cup winner, is 33 years old, and is very experienced. I spoke with him yesterday (Saturday) and we talked about the game and our team,” Alonso told the club website.
“He felt ready, and I don’t have to tell him many things for him to perform.
“Even today, while a goalkeeper wants to keep a clean sheet, I am happy with his impact. He has been in the building just 48 hours, so now we will have a whole week to prepare for the next one.
“Day by day, we will feel this presence because he has this charisma, this aura to influence and have a very positive connection with the rest of the team.”