With six laps remaining Alonso had 25 points in his hands, but at that stage he was fighting a losing battle as hopes of surviving on a one-stop plan rapidly fell apart.
In the space of just five laps and with the Pirelli tyres on his Ferrari degrading severely, Alonso plummeted from first to fifth, in the process losing his championship lead.
Although Alonso now trails new front-runner and race winner Lewis Hamilton by two points, he saw enough to suggest he and Ferrari are in the title hunt this season for the long haul.
"We tried to win, but the gamble of only making a single stop did not pay off," said Alonso.
"When Hamilton pitted for a second time we chose to try and play our hand.
"It's easy to say we should have made that choice too, but it would have meant we had tried nothing and we could also have lost position to Sebastian Vettel.
"But the last laps were very long indeed. The tyres dropped off suddenly and I was too slow to defend myself from those coming up behind.
"At least the car was competitive practically all race long. It wasn't the quickest because the McLaren, as expected, was very quick.
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"But we have definitely made a step forward in terms of performance, and for the first time this year we have not just been trying to limit the damage, in that we were actually aiming for the win.
"It's a positive sign and now we must confirm it at Valencia (European GP in a fortnight's time) and Silverstone (British GP on July 8).
"We are definitely returning home with more confidence in our chances because this was the most significant step forward we have made in terms of car development for a long time."
Team principal Stefano Domenicali feels qualifying is crucial for their hopes of world-title glory as Alonso has only been on the front row once this year.
The race at Montreal's Circuit Gilles Villeneuve also highlighted tyre wear for Domenicali, even if stopping just once was risky.
Domenicali said: "There's a certain feeling of disappointment and there's no point denying it.
"It's the first weekend in which we have not got the most out of what we had, but it's also down to the fact the level of expectation was higher thanks to the progress we have made.
"Let's not forget we were fighting for pole and were in the battle for the win right to the end.
"In Bahrain, a month and a half ago, we only got one driver into Q3 and we finished the race one minute off the winner.
"So we must continue to push on the development to close the gap which still separates us from pole position.
"Only when we have done this can we claim to have reached our first objective.
"Another theme we need to look into further is the tyre degradation which is proving to be ever more the key to this season."