He scored twice in a 3-0 win for the Italians at Anfield in their Europa League quarter final first leg.
Ahead of the second leg, Klopp told reporters: He was exceptional against us. He was really, really good in England we say he was a 'handful'! He is difficult to play against, great in the air and great on the floor.
I liked him when he was at West Ham, I didn't know him too well when he came to West Ham. It didn't work out there 100 per cent but that can happen because the Premier League is a difficult league to play but you can see he has great quality.
I don't know now all the other Italian strikers, to be honest, to compare them well, I know them all but I don't know who is contention to be the No.9 for Italy and who is not.
But for a specific way of playing I would say he is a fantastic option. He is a real focus player, he can bring the ball down, gives you time to push up, is a threat in the box, has speed as well: that's a really interesting package.
Yes, he made a big difference in that game but we didn't make it too difficult for him as well so we should make it a little bit more difficult tomorrow."