Singapore GP: Surreal to be making F1 debut - Alexander Rossi

American Alexander Rossi says it feels "surreal" to be making his Formula 1 debut this weekend after agreeing "a last-minute" deal with the Manor team.

He replaces Roberto Merhi in five of the remaining grands prix this season, starting in Singapore on Sunday.

Spaniard Mehri will take part in the races in Russia and Abu Dhabi.

"This is a major step in really firmly putting myself on the F1 map and I'm just focusing on doing a really good job in these five races," said Rossi.

"I was on a plane Tuesday evening, and I booked the flight Tuesday morning. The discussions started taking place shortly after Monza."

The 23-year-old, who will additionally race in Japan, the USA, Mexico and Brazil, partners Englishman Will Stevens.

He was previously a reserve driver for the now defunct Caterham team and took part in three practice sessions over the course of the 2013 and 2014 seasons. He joined Manor's forerunner Marussia towards the end of last year, before they also collapsed.

Rossi, who lies second in the GP2 feeder series this year, added: "Obviously I've had quite a bit of history with this team, in 2014, so we've always had good communication over the beginning of this year. But I wasn't expecting 2015 to be a year where I was racing an F1 car."

Merhi, 24, said he only found out he was not racing this weekend when he arrived in Singapore.

"I flew here on Monday and when I arrived the team gave me the news that I would not be driving, and Rossi would replace me for five races," he said.

"For next year, we don't know yet. We are looking for an F1 seat and we will try to find the best option possible.

"But now in these days it is really important [to have] the budget and at the moment it is hard to find some budget."