Everton boss David Moyes believes Nikica's Jelavic's arrival at the club inspired a 10 per cent improvement from the rest of the squad.
Jelavic scored nine goals in 10 Premier League starts following his January switch from Rangers with the Toffees losing just one of those games.
The Croatia forward's own form was clear to see, but Moyes believes his presence also raised the performance levels of those around him.
The 49-year-old Scot told Everton's official website: "What Jelavic did was make every player about 10 per cent better.
"Every one of them knew they could play the ball into the box and we would have a chance of scoring. They could use him to link up and he gave us a great lift."
Despite Jelavic's success, Moyes admits he was not convinced by the player until Everton coach David Weir was so insistent about his quality.
Weir had played alongside the 26-year-old at Ibrox and persuaded Moyes to swoop.
"A little while ago Jelavic looked as if he would be nine or £10m from Rangers which we wouldn't have been able to afford," added the Everton boss.
"I watched him twice for Rangers against Celtic and wasn't entirely sure, he hadn't played that well in the games.
"But I brought David Weir back into the club and he kept talking to me about him and in the end we rustled up the cash.
"It was about £5m after (Diniyar) Bilyaletdinov went back to Russia, and I have to say he has been great. He is what Everton needed - we really needed a centre forward.
"He has exceeded expectations. You buy someone like that and what could you sell him for? I assure you we are not going to do that but if we did then it would give us a great turnaround.
"But what we want to do is build a good team at Everton. We have done (in the past) and we will continue to do so."