Fernando Alonso labelled qualifying fifth fastest for the Indy 500 a "dream" after again impressing.

The two-time Formula One world champion and McLaren Honda Andretti entry will start from the second row in Sunday's race.

Scott Dixon will start from pole at Indianapolis Motor Speedway, but Alonso has seemingly adjusted to IndyCar relatively smoothly.

Alonso was delighted with his efforts, expressing his surprise at qualifying fifth fastest.

"With everything that has happened today being among the top 5 is a dream! 15 days ago I would never have thought about fighting for the pole," the Spaniard wrote on Instagram.

"Thanks to the whole team!! Now another week of learning and race next weekend."

Ed Carpenter, Alexander Rossi and Takuma Sato were the other drivers to qualify ahead of Alonso.