The midfielder got a vital goal in a win over Gent in the Europa Conference League in midweek.
As the Blues rotated their team, Maresca got to try out players who are not regular starters.
He stated: "I know Kiernan very well from last year. I completely understand how difficult it is in this moment for Kiernan in terms of he was the main player at Leicester, you join Chelsea and you become one of the players.
“You are on the bench, you are not in the squad, you are not playing from the start, so you struggle a little bit at the beginning.
"But he needs to understand the reason he is here is because we want him. The celebration (from Maresca) is probably because I know he needs that. This is the reason why."
On fellow goalscorer Renato Veiga, Maresca said: "It's similar to Cesare Casadei in terms of physicality. He is tall, he is big. Tonight he played like an attacking midfielder, in the pocket for the first time of the season for us. He did very well. You never imagine Renato arriving in the box and scoring from the other side. That means he is doing well.
"When we needed him as a holding midfielder against Bournemouth, he was there. The other day against Brighton, as a full-back. He is versatile. Tonight he was playing like an attacking midfielder but overall I think he did well."