Red Bull's Marko says F1 test proved Carlos Sainz Jr is ready

Sainz was confirmed on Friday as Toro Rosso's second 2015 signing to partner Max Verstappen, three days after he completed 100 laps for Red Bull's senior team in testing at Yas Marina.

Marko, who has mentored 2014 Formula Renault 3.5 champion Sainz during his time on the Red Bull junior programme, said that the Spaniard's performance showed that he was the right choice for a race drive next year.

"The test in Abu Dhabi in the Formula 1 car was what really confirmed to us he was the right man for the seat," said Marko.

"He proved that he is ready for Formula 1. He had a very successful test.

"He did 100 laps, the speed was good, the technical feedback was good.

"He's done everything we expected, so I'd say he was the natural choice."

Sainz's F1 hopes were thrown into doubt earlier this year when Red Bull made the shock decision to give Max Verstappen a drive with Toro Rosso for next year, and Marko acknowledged that both were deserving of a place on the 2015 grid.

"Carlos convinced us with winning this year's World Series title with a record of seven wins," Marko added.

"Nobody in the history of the series has matched Carlos in that regard. He has matured a lot in the last two years.

"Maybe Verstappen was a little bit of a surprise, but if such a talent comes up you have to go for it.

"I am looking forward to seeing these young guys having their first season and we are confident that they will do very well."