The midfielder was keen to praise the pair after they impressed in the win over Chelsea.
The Reds ran out 3-1 winners at Stamford Bridge, with Coutinho proving the difference as he scored the equaliser and then put his side into the lead before Benteke wrapped up the victory.
It was a fine return to form for the Brazilian midfielder, who has struggled to replicate the kind of performance levels that Liverpool fans became accustomed to at the start of the 2015/16 campaign.
And Lallana says it was great to see him looking more like his old self.
“It’s great to see him playing like that. He’s such a talented player. He’s a little gem,” he told liverpoolecho.co.uk.
“Okay, he hadn’t been playing as well as we knew he could but it was always just going to be a matter of time before he got back to his best [but] Philippe is a class act - everyone knows that.”
The midfielder was also keen to praise Benteke, saying his contribution to the game was 'massive'.
The Belgian was thrown in off the bench by manager Jurgen Klopp, and made his presence known as he bullied an already fragile Chelsea back line.
His introduction into the game saw the Reds go more direct with their play at times during the second half, and Lallana says that is of great benefit to the team as he offers them a new dimension to their game.
“Christian’s contribution was also massive,” he added.
“He had a great impact from the bench. He came on and gave us a completely different dimension. We’re going to need the whole squad this season if we’re going to do well in each competition and they are two big players for us.”