McLaren driver Fernando Alonso vented his frustration over the Formula One team's lack of competitiveness, claiming they look like amateurs.

Two-time F1 champion Alonso endured a forgettable race at the Canadian Grand Prix after he was forced to retire as Lewis Hamilton triumphed on Sunday.

Alonso exchanged words with McLaren, responding angrily to team orders to conserve fuel by arguing the embattled manufacturer risk appearing as amateurs if they reduced their pace in Montreal.

The Spaniard was heard on radio saying: "I don't want, I don't want. I have really big problems now, driving with these and looking like amateurs... So I race and then I concentrate on the fuel."

Post-race, Alonso attempted to explain his stance.

"When you are in the middle of a battle, fuel is a low priority and you will find time later on," he said.

"After three or four reminders of fuel, I just said let me race and let me have some fun.

"We are like a different category. When everyone passes you so easy like that, you look like an amateur driver and that is not good. We are not super competitive now.

"We have many things to do in our case, but hopefully this weekend has given us some lessons."

Alonso, who retired for the third consecutive race and fourth in total this season, added: "It is what it is. I know from the outside, they all want to crush us. We are going through a bad streak and we can't do anything else, but continue working.

"You need to understand I believe in this project - all the program of developing the car is quite positive.

"I know it is difficult for the fans, but they need to be patient and they need to believe because something good is coming."