Briscoe, who came into the race at the Mid-Ohio Sports Car Course with the lead in the drivers' standings, now trails Sunday's race winner, Scott Dixon, by just three points with four races remaining in the 2009 season. The IndyCar season resumes on Aug. 23 at Infineon Raceway in Sonoma, California.
Briscoe worked hard to keep the No. 6 Team Penske Dallara/Honda ahead of Dario Franchitti's car during the final laps of the race, eventually claiming second place by three-tenths of a second.
"We were dynamite out of the pits on the last stint, and it kept up that way for about four laps," Briscoe said. "Then our lap times dropped off about a second. I was pretty scared because we still had about 15 laps to go. I thought, ‘This is going to be terrible if it keeps dropping off.' But after that I was able to maintain a pretty decent lap time. It was good enough that I was able to hold off Dario."
Meanwhile, Team Penske's Helio Castroneves recovered from a mid-race spin to finish 12th, but ultimately lost some ground in the championship chase. Castroneves remained in fourth place in the standings, but fell 101 points behind Dixon.
"Obviously, I'm very disappointed with our result today," Castroneves said. "We lost it in Turn 9 and we dropped back in the field. We tried a different fuel strategy than the other guys, but it just didn't work out in our favor. Now we just have to move on and look toward Sonoma."
The runner-up finish was Briscoe's sixth in 13 races this season. He started from the pole position Sunday and led twice for a total of six laps, but couldn't threaten Dixon in the second half of the race.
"It was a lot of hard work out there," Briscoe said. "I was holding off Scott and Justin (Wilson) at the beginning, but I could see that Scott was fast. A couple of times I put in really good lap times, and he'd still be right there behind me. He just wouldn't let up, so I knew he was going to be fast throughout the race."
Still, Briscoe said he likes his championship chances because of Team Penske's strong history in the final four races of the season.
"There have been 13 changes in the lead in the championship, which is really incredible," Briscoe said. "It's the first time for me to be in the middle of the championship, and I'm excited about that. It's been a fantastic year. I feel like I'm still learning and gaining experience with every race."
Following the Infineon race on August 23, the IndyCar Series moves to Chicagoland Speedway on August 29 before traveling to Twin Ring Motegi in Japan for another oval race September 19. The season finale is set for October 10 at Homestead-Miami Speedway.