Stewart admits disappointment with Alonso in 2010
The famous Scot, who celebrated his 71st birthday at Montreal's Circuit Gilles Villeneuve on Friday, admitted he openly wanted to see the Spanish double world champion move to Maranello based Ferrari this year.
"He is a very clever driver and he has the necessary qualities to do the job that Schumacher once did. He is a leader," former three-time F1 title winner Stewart told Spain's AS newspaper.
But after Alonso won his first race with the famous Italian team in Bahrain, the results have not flowed.
"It is taking more time than I had expected," Stewart explained.
"He has made more mistakes than is usual, and the car is also falling short," he added.
Alonso, 28, said in Canada that he refuses to accept his Ferrari title challenge might need to wait for the 2011 campaign.
"I think we are in a good position to fight for this championship," he said after going second fastest in Friday's afternoon practice session.
"There were some races better than others but we need to be not too high when we win and not too low when we don't perform."