Carlos Sainz is confident McLaren will put itself back on track in 2019.

Flavio Briatore, who is a manager of retiring McLaren driver Fernando Alonso, says the once great British team's car has been "disastrous for years".

Replacing the Spaniard from next year is another Spaniard, Carlos Sainz.

"I think they are doing their homework now," Sainz told Cadena Ser radio.

"They hit the bottom this year so they can only get better. They're starting from scratch and that gives me confidence. They've seen the problems and they want to stop them," he added.

Sainz thinks McLaren's gradual slide even further back this year is because the team has been focusing for some time on 2019.

"I hope so," he said. "I think McLaren this year, the car and the team, were not fighting for more this year, so I hope they did bet on next year and that this was the learning year.

"Next season there is a change of regulations and it's an opportunity to start from scratch and reach the required level," Sainz, currently a Renault driver, added.

"My car now is not bad and the McLaren is three or tenths worse. But the gap to the rest of the grid is a world and that makes them look even worse.

"It's an odd thing to see Alonso nearly last, but this half of the grid is so tight that three or four tenths is a lot," he explained.