Oriol Servia of Spain drives Justin Wilson's No. 25 car during practice for the IndyCar auto race Friday in Sonoma, Calif. Servia was chosen to drive the car in tribute to Wilson of England, who died Monday from injuries sustained at Pocono Sunday. — AP SONOMA, Calif. — Justin Wilson was on the minds of IndyCar drivers as they got back to work Friday less than a week after the British driver died of injuries suffered in last weekend's race. Three of the six series championship contenders were among the five fastest in the first practice session for Sunday's season-ending Sonoma Grand Prix. Reigning series champion Will Power's year-old track record of 1 minute, 17.2393 seconds, set in qualifying on the 2.385-mile (3.84-kilometer), 12-turn road course, will be challenged in the three rounds of qualifying. Power, who is fourth in the standings, recorded the quickest lap of 1min 17.4858sec Friday in his Penske Chevrolet. American Graham Rahal, who is 34 points behind championship front-runner Juan Pablo Montoya entering the season finale, was .1326 of a second outside Power's top time. Ryan Hunter-Reay, who has won two of the past three races, was third-fastest and three-time series champion Scott Dixon, third in the standings, was fourth-quickest. Penske driver Montoya was ninth fastest in Friday's practice. Brazilian Penske driver Helio Castroneves noted in an article written for Sports Illustrated's website Friday that racing less than a week after Wilson's death is “difficult.” Wilson died Monday, a day after debris from another driver's crash hit him in the helmet late in the race at Pocono Raceway in Pennsylvania. Reminders of Wilson are everywhere, with Spain's Oriol Servia driving Wilson's 25 Andretti Autosport Honda this week as a tribute. IndyCar has produced a memorial T-shirt for sale to benefit a fund for Wilson's two young daughters, and teams have been given memorial decals to put on their cars. “It's hard for the words to come out the right way,” Servia said when asked about his friend Wilson. “I have known and raced Justin for more than 10 years. I have an enormous amount of respect for him as a racer, but his qualities as a human were definitely an inspiration to anyone who ever met him.” Added team owner Michael Andretti: “We will have Justin and his family in our hearts this weekend as we honor him in the way he would want us to — by doing what he loved: racing.” The loss of one of the most popular drivers in the paddock has been difficult for his peers, but many said Wilson would have wanted Sunday's season finale at Sonoma Raceway to go on. “People don't realize for us, we've been doing this a long time. It's our most comfortable position,” said three-time Indianapolis 500 winner Helio Castroneves. “We've still got to remember it's racing. There is the unfortunate danger factor of it. I do feel it's the best place ever where I'm in control, that I feel I can do whatever I want. That's why it's the best way to be here today.” Decals honoring Wilson have been distributed to teams to place on the cars, and T-Shirts were creating with the same logo with 100 percent of the sales proceeds going to a fund for Wilson's daughters. Both Honda and Firestone have made results-based pledges for the weekend, with a combined $95,000 potentially going to the fund. The series is still confronted with questions about safety, though, particularly in a season that has been marred with various accidents. Now the series is being questioned about the safety of open cockpits following Wilson's death. — Agencies