Carlos Sainz's positive perfomance against his team mates was one of the reasons that prompted Mclaren to sign him for the 2019 season.
Carlos Sainz was up against Sergio Perez, Esteban Ocon, Lando Norris for the seat at Mclaren.
Mclaren analysed each drivers performance against their team mates and Carlos impressed them the most.
"We did a fair amount of analysis, and he showed well against the different team-mates he's had in the past," McLaren's new Sporting Director Gil de Ferran told Formula1.com.
"Even though he's still a very young man, next year will be his fifth season in F1, so I would consider him an experienced driver."
"When the opportunity came up to sign him, we jumped at it. He's intelligent and dedicated. He's got a great deal of potential."
Meanwhile Carlos Sainz says he is up for the huge task that awaits at Mclaren.
"It's a huge task to try and match the performance of McLaren to Mercedes or Ferrari," he says. "It's going to take time."
"I'm probably in the first half of the year maybe leading the team towards one direction or the other. But in the end, I'm a strong believer that in F1, number one and number two doesn't exist."
"I believe the team will treat us both as number ones, because that's exactly what the team needs at the moment, both pushing each other flat out to help the team move forward."
"It will be more than an honour for me to take a bit of a lead, but I'm sure Lando has things to say."