Liverpool manager Jurgen Klopp praised Fabinho's performance against Ajax, while insisting he was unsurprised by the Brazilian's display.
With Virgil van Dijk sidelined due to a serious knee injury, Fabinho started at centre-back alongside Joe Gomez as Liverpool opened their Champions League campaign with a 1-0 win in Amsterdam on Wednesday.
As well as producing a goal-line clearance to deny Dusan Tadic, Fabinho had four tackles, nine clearances and four interceptions.
Klopp was pleased with the Brazil international as Nicolas Tagliafico's first-half own goal proved to be enough for Liverpool in Group D.
"This combination with Joey and Fabinho, I don't think they played together before if I'm 100 per cent right. Maybe once but I don't really know," he told a news conference.
"So they need to get used to each other, they need to get used to the verbal demands in that position – what you have to say there to help the midfielders and all these kind of things.
"It was a really good performance but there's a lot to improve – how high or how low is the last line in which moment, in protection situations, in the pressing, 'How do we react there?' But it's no problem. It was absolutely good and now we carry on."
With Van Dijk set to miss most, if not the remainder, of the rest of the season, Fabinho will play a key role for Premier League champions Liverpool.
Klopp, whose team host Sheffield United in the Premier League on Saturday, said while the 26-year-old's performance was a boost, he was unsurprised.
"Look, in our situation it helps. Of course, was there pressure on the situation? Yes, it's clear for the two in the back there, 100 per cent. First game together," he said.
"Fabinho can play the position, he likes playing it actually. If I would have asked him to play right-back I don't think he would enjoy it as much as he's enjoying the centre-half position. In our situation in the moment we have to keep those boys fit and then they can of course help us a lot. I'm not surprised he plays well in the position otherwise we would have thought about a different solution, even when that would have been properly tricky.
"I'm really pleased for tonight, pleased for him, yes it gave him confidence, for sure helped us. These situations [goal-line clearances], Millie [James Milner] had last season one against Bournemouth, which was a massive one. That tonight was a massive one. And so he had not only because of this a big hand in this victory."