Alexander Rossi 'on the pace' in IndyCar test debut with Andretti

The 24-year-old Californian has raced in European single-seater ladder series since winning the Formula BMW Americas title in 2008, and made it to F1 for a part-season with Manor last year.

With Manor picking Pascal Wehrlein and Rio Haryanto for 2016, Rossi will return to America and race the fourth IndyCar entry Andretti is running in collaboration with Bryan Herta Autosport.

Rossi described his first test in the car at Sebring this week as "positive so far".

He added: "The car is pretty similar to other things I've driven.

"There's quite a bit of downforce, which is fun for a driver to have.

"At the end of the day, it's an enjoyable car to drive and I'm looking forward to racing it next week."

Most of the IndyCar field was in action at Sebring over the test days this week.

Although no times were released, Rossi believes he was competitive.

"The first set of tyres was a bit of a learning experience, but I think by mid-morning yesterday, we were on pace with everyone else," he said.

"The adaptation came pretty quick, now it's just working on test items.

"I think we're pretty pleased with the way the team has come together and performed as a whole."

The IndyCar season begins in St Petersburg next weekend.