Alexander Rossi said he was hoping to secure a permanent seat in Formula One after becoming the sport's first American driver in eight years at the Singapore Grand Prix.
Rossi, who chose racing number 53 for his car in honour of the "Herbie" films, has just five grands prix to make his case after being drafted in by British back-markers Manor.
The 23-year-old debutant escaped a high-speed collision with the barriers in first free practice before outpacing Manor team-mate Will Stevens in the second session late on Friday.
"I've got five races to show what I'm capable of," Rossi told AFP at the Marina Bay Street Circuit, describing a permanent seat as his "ultimate goal".
"It's a difficult situation considering we're a bit off the pace of the other cars, so it's not about beating the other cars, it's about showing what I can do against my team."
Rossi only found out on Tuesday that he would replace Roberto Merhi for five of the year's last seven races, and was rushed out to Singapore on the next available flight.
He will skip Russia and the season-ending race in Abu Dhabi to return to the GP2 championship, where he is second in the standings.