BIRMINGHAM, Ala. -- Spencer Pigot remained perfect in the Pro Mazda Championship Presented by Cooper Tires, sweeping both of the races at Barber Motorsports Park and extending his unbeaten streak to four.

But, once again, he had to work hard as 2013 USF2000 champion Scott Hargrove took the pole and pressured Pigot through most of the 20-lap race on the 2.38-mile, 17-turn road course.

Hargrove started from pole position for the fourth round of the championship. The 19-year-old Canadian was unable to solidify his advantage at the start, however, as Pigot remained on his outside all the way around Turn 1, which gave him the preferred inside line heading into the long, right-handed Turn 2. It was an aggressive move by Pigot, and ultimately one that would prove decisive.

The race was neutralized briefly on Lap 2 due to a spin farther down the 20-car field, and at the restart Hargrove redoubled his efforts to regain the advantage. Several times he drew alongside Pigot's Doug Mockett & Company/Rising Star Racing/Vitamin-DPro App/California Scents-Juncos Racing entry, but each time Pigot was able to hold him off.

The two leaders traded fastest laps as Hargrove continued to pile on the pressure before Pigot edged out a slight advantage by half-distance. The gap grew slowly but steadily thereafter as Pigot sealed the additional championship point for fastest race lap.

"I knew going in that as long as I had one wheel alongside Scott, I was going to go for it," Pigot said. "Luckily, I had a little more than that. I was alongside or even a little bit ahead. It was a bit closer than I would have liked but that's what you get for starting second. You never know when you go side by side what's going to happen on the exit. We were as close as we could get without touching; I'm actually surprised there isn't some rubber on the side of the car.

"It was some really good, close racing."

Hargrove's second runner-up finish in as many days with the MAZDASPEED/Analytic Systems/Race Energy/Metal Action Machining car for Cape Motorsports with Wayne Taylor Racing marked his third consecutive podium, bringing him equal on points with Kyle Kaiser, who finished fifth in Race 2 for Juncos Racing.

Shelby Blackstock made a fine start to jump ahead of Neil Alberico (Cape Motorsports with Wayne Taylor Racing), as did Pipo Derani (Team Pelfrey), who overtook Juncos teammates Kaiser and Jose Gutierrez at Turn 1 and Turn 5, respectively, then found a way past Alberico at Turn 8. Alberico lost another position to Kaiser at the restart, after which the top six positions remained static.

The next two rounds of the Pro Mazda Championship Presented by Cooper Tires, the Allied Building Products Grand Prix of Indianapolis, will be held on the new Indianapolis Motor Speedway road course in support of the Verizon IndyCar Series' Grand Prix of Indianapolis on May 9-10.