Hartley: I wasn't ready for F1 at 18, but I am now

2017 24 Hours of Le Mans Le Mans winner Brendon Hartley feels he is now ready to race in Formula 1 and make his debut with Toro Rosso in this weekend's United States Grand Prix, despite not knowing the car.

Hartley was part of the Red Bull junior programme from 2006 until 2010 when he was dropped by the energy drink giant, leading him to move into ELMS and then find his way to the FIA World Endurance Championship, where he became world champion in the LMP1 category alongside Mark Webber five years later.

Speaking about the surprise call-up to race at the United States Grand Prix, Hartley said" "When it was announced Porsche would stop endurance racing in LMP1 for next year, I called Helmut Marko and I said: 'You know what, I'm a different driver from 10 years ago. I've learnt a lot and if there's ever an opportunity I'm ready.'"

However, the immutable head of the Red Bull driver programme remained tight-lipped: "He didn't say much. He just said he got the message and three months later I got the call and this happened very quickly."

Hartley has been called up for, in principle, a one-off race with Toro Rosso, and is one of their oldest debutants for some time at 27. However, the Porsche works driver is rumoured to be in line for a drive for the rest of the season should he impress in Austin.

Speaking about why he didn't get his shot at F1 in 2010, Hartley said" "I guess I wasn't ready. I had some success in the early days and won the Formula Renault, I became the reserve driver at my first F1 test at 18 years old and I guess I didn't really deal with the pressure. I stopped enjoying it.

"I wasn't happy. I was pretty young, away from home and I guess when the Formula 1 dream stopped in 2010 I picked myself up, I started endurance racing and I learned a lot from that experience with being in the LMP1 programme.

"I wasn't ready, at 18 years old. I like to think I'm ready now."

Speaking about coming into Formula 1 mid-season, in a car many drivers still call challenging Hartley said: "I'm not very prepared. I haven't driven the car and I haven't driven a single seater since 2012 but I like to think Porsche LMP1 has hopefully prepared me well.

"It's certainly nice having my debut on a track I know very well. I think learning the car will be the bigger challenge, the big tyres, the big downforce the Formula 1 cars have at the minute will be pretty tricky. Obviously these guys are setting lap records at every track they go to, but I'm looking forward to it."

Despite suggestions he could land a more permanent role with Toro Rosso, Hartley stressed he was "just focussing on the weekend."