Carlos Sainz has filled a void at Renault - Prost

Carlos Sainz' maiden race with Renault was a resounding success but more importantly, the Spaniard's presence has filled a crucial void says Alain Prost.

Sainz has been loaned to the French team by Red Bull for the remainder of the season and 2018, and the 23-year-old lost no time in marking his territory, with a P7 finish in Austin.

The performance and subsequent result validated the team's push to have Sainz join the works outfit from Toro Rosso this year, says Renault Ambassador and special advisor Alain Prost.

The four-time world champion believes Sainz is now a crucial asset to the team in terms of its ability to score points consistently with both its drivers, an advantage which it could not achieve previously with Jolyon Palmer.

"It's always a small risk that you take when you change a driver in the middle of the season, but in fact it was exactly what we wanted to have," Prost told Motorsport.com.

• Renault's Abiteboul ecstatic over Sainz debut

"We had unfortunately a problem with Nico, and we had Carlos to get points. If you want to build something, you cannot have a big hole somewhere.

"It's not being rude with Jolyon, but we are constructors and we need to have everything not perfect, but better, and we know we have a lot to do still.

"We are not going to develop [the car] very much, so we want to have the two drivers doing more or less what they have done.

"I hope we don't have reliability problems, and get the two in the points in the last three races, if possible."

Unfortunately, Sainz's future still remains in Red Bull's hands, a state of affairs which could lead to his return to the energy drink family in 2019 if his presence is required. Renault has decided to accept that risk however.

"In this situation we don't have all the keys, but the market is very open next year," he said.

"There is no reason why we should change, but because we don't have all in our hands, we have to wait a little bit.

"We are lucky to get Carlos, because we wanted him, but we don't have him for the long term, so we have to be careful.

For us, that's not a problem. We are in a period where we are building, so the timing is okay. We want to establish a strong relationship with him."

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