"When I first came to Roma, I didn't know a thing about Aquilani," said Riise.
"I knew all about Francesco Totti, Daniele De Rossi and Philippe Mexes, of course, but Aquilani was the player who surprised me the most in my first months with what he could do.
"He's really good on the ball, with good passing, good movement, he works hard and is a good professional.
"He likes to have the ball at his feet but not because he likes to dribble, he just wants to keep the team moving. He never stands still, he's always on the run.
"He certainly runs more than Xabi and is probably more dangerous in terms of getting in the box and trying to score goals.
"When I came to Rome he was my neighbour and helped me out a lot. He's a good friend. Liverpool will be getting a very good player.
"There is an obvious difference between the Italian and English leagues.
"Here it is more tactical whereas in England you're playing 90 minutes up and down, up and down, and there is more emphasis on power and physical force. But Cristiano Ronaldo isn't all about physique and he has been the best player in the Premier League in recent seasons.
"Everyone can adapt. It just takes time. The key is how long it takes. I was lucky - I fitted in quite quickly when I came from Monaco. Alberto is someone who wants to make the most of his talent and wants to prove himself, so if Liverpool come in for you it is very hard to say no."