Fernando Alonso showing he 'gets' ovals with Indy testing

Alonso completed the mandatory laps at set speeds in his first hour of testing on Wednesday, and Andretti said the way he was working his way around the track on the early runs proved he can be competitive on his IndyCar debut.

"He did perfect, everything that he was supposed to do - got through all three phases [of ROP] so now we can go play a little bit," said Andretti.

"He's looking at data right now... so he can see what's on the data compared to what he's feeling out on the track.

"He gets it; he's one of the best in the world and you can see why.

"He watched what he was doing with his line, he was changing it up lap after lap to get a feel.

"He had a little bit of understeer and he adjusted his line for the understeer, so, you know... he's the real deal.

"He was experimenting. One time I thought he was a little low but then the next lap he got it back up there a little bit, so it was good."

Andretti added that his team will "probably get into a couple of trims" in terms of aerodynamic set-up to give Alonso a feel for varied levels of downforce.

Asked if it still felt like a big deal now Alonso has been on track, Andretti said: "When Zak [Brown] and Mark Miles called me, I was like, 'OK, I don't know how we're going to do this but we're going to do it, we're going to figure out a way to get it done'.

"It's too big of a story, too big of a deal for our team, to have somebody like Fernando running with us, and being associated with McLaren - it's just a fantastic opportunity for us that we were not going to let slip by."