Colton Herta earned pole position for the second race of the weekend at Mid-Ohio after topping a rain-hit qualifying session that involved a crash for race one victor Will Power.
The 23-driver field was split across two qualifying groups, with the drivers from the fastest group occupying the odd-numbered places on the grid and the drivers from the slower group taking up the even-numbered spots.
It was Dale Coyne Racing's Santino Ferrucci who starred in the treacherous conditions to top the first qualifying group by over 3.2 seconds ahead of his team-mate Alex Palou.
Ferrucci put himself firmly in contention for a maiden IndyCar pole with a benchmark time of 1m27.4688s amid an interrupted session.
The first red-flag stoppage was caused by a crash for AJ Foyt Racing's Charlie Kimball who spun at the end of the start/finish straight.
Palou recovered from spinning twice on his outlap to set the second-fastest time in the first session, ahead of 2016 series champion Simon Pagenaud and Andretti Autosport's Ryan Hunter-Reay.
Pagenaud's team-mate Power, who dominated the opening race of the weekend at Mid-Ohio from pole position, spun just moments into the second session and brought out the red flag with Jack Harvey slamming into the wall at a similar time.
Power returned to the pits but was unable to re-join qualifying because he - along with Meyer Shank Racing's Harvey - was responsible for causing the red flag.
Almost immediately after the session restarted, Arrow McLaren SP's outside title contender Pato O'Ward spun into the gravel and the red flag was required once again.
When the session eventually restarted it was Andretti's Herta who topped the session with a 1m26.2788s - fast enough to ensure he'll start from pole position alongside Ferrucci.
Championship leader Scott Dixon will start from third place ahead of Super Formula convert Palou and his Chip Ganassi Racing team-mate Felix Rosenqvist.
Pagenaud will start in sixth ahead of Marco Andretti, who gambled on slick tyres and set the fourth-fastest time in his group with a late-effort.
The top 10 on the grid is completed by Hunter-Reay, reigning series champion Josef Newgarden and Alexander Rossi.