The Brazilian may be a defensive midfielder by trade, but had to fill in at centre-half against Ajax on Wednesday.
And he put in an excellent display as the Reds came away with a 1-0 win away in the UEFA Champions League group stages.
Fabinho was the team's man of the match as they shut out their Dutch opposition.
"It's always important to start well, it was a tough away game first up so that's a bonus and they're a good team," Milner told BT Sport.
"They were well organised, played good football and we've had an up and down week and so it was important to bounce back which we did and I expected nothing less from this group of players.
"Fabinho is a top player and top players can adapt and he did that. He's played there before and played very well. I thought it was a good team performance because it was tough out there, it was a physical battle under tricky conditions.
"We'll take anything in relation to a goal, we had enough chances, we were disappointed not to score more. We had a good number of counter attacks which we didn't finish off. It's a big clean sheet, with the changes we've made this week especially and they're a good team, so it was important to get the clean sheet and take the points."