Battling the sun in 85 degree heat, Tom Zirbel crossed the finish line at the top of Chilkoot Hill on Sunday as the wire-to-wire champion of the 2015 North Star Grand Prix.

After placing first at the St. Paul riverfront time trial on Wednesday and winning both the Menomonie and Stillwater race courses on Saturday and Sunday, the team Optum/Kelly Benefit Strategies rider cruised to an overall event victory.

“It’s just a great team effort,” said Zirbel, who also won the event in 2012 when it was called the Nature Valley Grand Prix. “My team took care of me all day today. And even yesterday setting me up for the breakaway, it wasn’t just me, it was all five guys. Guys really stepped it up, and we’re really pleased to get the win here again.”

Fabrizio VonNacher of team KHS-Maxxis-JLVelo placed first at Sunday’s Stillwater individual stage with a time of 1:30:00 and was followed by Donkey Label Racing’s Ben Hill (1:23:01) and Kevin Girkins of Elbowz Racing (1:23:06).

Also competing in the race was Carmen Small, a contender for a spot on the 2016 Rio de Janeiro Olympic team and the winner of the 2015 Union Cycliste Internationale World Championships.

Earlier in the day, Jennifer Rife of Birchwood Cafe won the women’s amateur criterium with a time of 44:51, and Melissa Dahlmann of the St. Paul Bicycle Racing Club finished a second later. Jameson Ribbens of Revolution Cycle/Twin Six won the amateur men’s criterium with a time of 51:04.

Cyclists at the North Star Bicycle Festival, which included men’s and women’s amateur races as well as the professional North Star Grand Prix, faced the daunting Chilkoot Hill. An estimated 3,000 fans surrounded the 2-mile course, with most lining Second Street by the Chilkoot Hill finish line.

The hill has an 18 percent increase grade, three times steeper than the incline limit for hills on national highways, and was a major struggle for racers all day.

“For me, [the hill] is all about survival,” Zirbel said. “I’m not going to win this stage. I’m a big guy.”

For Zirbel, Sunday’s event victory was the culmination of a week’s work.

“It all starts with day one and the time trials setting ourselves up,” the Iowa native said. “… That just gives us options in the road races. It’s a really hard race to control start to finish. We see breakaways winning the overall every year, so it’s just a matter of having the numbers for those breakaways.

“It’s got a good time trial for me, and we always bring our strongest team here. We have a lot of Minnesota sponsors, so this is one of the biggest races on our calendar.”

Zirbel will take a little over a month off before competing in the Tour of Utah Aug. 3-9.