Sherrod Brown raised an eye-popping $5.8 million in the third quarter for his crucial Ohio reelection race.

Sen. Sherrod Brown raised an eye-popping $5.8 million in the third quarter of this year, leaving the vulnerable Democratic incumbent with a pile of cash heading into a tough reelection campaign.

Though many incumbents and candidates are still releasing their numbers, Brown’s haul is the biggest announced so far for this quarter. He will report having $11.2 million on hand, his campaign said. Brown’s race is sure to be one of the most expensive in the country next year.

Two of the incumbent’s potential GOP rivals, Matt Dolan and Bernie Moreno, announced fundraising hauls which included millions in self-funding. Rachel Petri, Brown’s campaign manager, dinged both in a statement as “multi-millionaires running to take on Sherrod [who] had to cut themselves fat checks in an attempt to buy Ohio’s Senate seat.”

Brown is in one of the toughest races in the country, along with Sens. Jon Tester (D-Mont.) and Sen. Joe Manchin (D-W.Va.), though Manchin hasn’t announced whether he will run yet. Several other Democratic incumbents released strong numbers this week that still fell far short of Brown’s total.