Motor racing legend Mario Andretti believes Fernando Alonso's talent is currently being wasted but sees improvements on the horizon for both the Spaniard and McLaren.

After a productive reprieve from F1 at Indianapolis , Alonso will be back behind the wheel of his MCL35 for the Canadian Grand Prix next week.

While the two-time world champion's plans for next year have yet to be finalised, Andretti was among those who is urging Alonso to consider a full-time switch to IndyCar.

"The only thing that keeps a driver happy is to be competitive," the 77-year-old told Spain's Marca.

"Anything else is total frustration. He is in the best phase of his career and wasting his time. McLaren obviously feels the same pain because it's a team that only knows how to be with the best."

Andretti believes however that there are better times ahead for both McLaren and Alonso.

"It can only go better for him," he said.

"It looks like they have a (good) chassis, and the situation with the engine will improve. I'm sure he'll be in the points before the season is over."

He also said Alonso was right to have sat out Monaco in order to try to win at Indianapolis, even though it was a familiar Honda engine failure that let him down.

"I guarantee that his value has gone up," said Andretti, "and he deserves the respect he gets. There were no losers here, except for the engine."

Want to win a trackday experience? All you have to do is subscribe to our FREE newsletter HERE

Gallery: All the pictures from Sunday in Monaco

Keep up to date with all the F1 news via Facebook and Twitter