The Norway international said: "At the time, I was injured - and we obviously needed a new striker. Emile is a great player, and I think it was a great move from the club to get him here in January.
"It definitely improved the competition, and you need plenty of good players at a football club. It made every player - particularly those of us up front - raise their levels.
"There's no doubt he's been a great signing - 100%. You always need a bit of time to settle in and find your feet.
"It took me about six months after I came to Villa from Lyon. You are at a new club with new players.
"I am sure Emile has yet to reach his peak here - but he has a lot to offer because he is a really, really good footballer. I am sure we will see that even more next season."