SPARTA, Ky. - The man Indy Racing League fans lovingly call "Spiderman" once again is at the top of the IndyCar Series standings.

But forgive Helio Castroneves if he's not yet planning a fence-conquering victory climb ¡ª such as the one he famously unveiled after winning his first Indy 500 in 2001 ¡ª if he finally wins the points title.

Castroneves leads Marlboro Team Penske teammate Sam Hornish Jr. by eight points heading into Sunday's Meijer Indy 300 at Kentucky Speedway, with Dan Wheldon and Scott Dixon within 31 points of the lead.

And while Castroneves knows winning a season points championship is the only hole in his otherwise sparkling resume that includes two trips to Victory Lane at the Indy 500, he's been around long enough to know how quickly things can change.

"A championship is something I really want, we're close," Castroneves said. "But it's challenging. You think you're having a great year, and then it's like all of a sudden, 'Oh.'"

Castroneves would know. He finished second to Hornish in the 2002 points race and was third in 2003 before sliding down to sixth last season as the Toyota engines used by Team Penske strained to keep up with the teams using Hondas.

In a way, the ingenuity Team Penske had to use while playing catch-up paid off when the entire IRL switched to Honda engines this season.

Instead of finding an extra tenth of a second where they could to keep up, Castroneves and Hornish now find themselves using that extra tenth of a second to pull ahead. As a result, they've dominated the series this season, winning seven of the circuit's 11 races and grabbing seven poles.

"Before, Honda was the dominant power in IRL and we were competing hard to just get thirds and sevenths," Hornish said. "Now, we haven't been to a place (this year) where we haven't been competing for a win."

That leaves it up to the drivers ¡ª and a little racing luck ¡ª to determine the champion.

Castroneves and Hornish have been trading the points lead for most of the season, though Hornish seemed to have a firm grip on the top spot before the Firestone Indy 400 at Michigan on July 30. But a broken water pump sent him to a 19th-place finish, erasing a 30-point lead.

"To go from 30 points up to eight points behind is a pretty big hit in one race," said Hornish, whose three wins this season include the Indy 500. "But the key from here on out is going to be consistency, the one who manages to stay consistent is the one who is going to win."

Unlike their 2002 season points battle, when Hornish won the final two races to hold off Castroneves, this championship chase is different.

Then they were rivals, now they're teammates, making for a slightly more complex relationship. While they compare notes before every race, things change when the green flag flies.

"On one hand, there's nobody you want to beat more than your teammate," Hornish said. "But if you can't win, you want him to win more. The way I look at it, I want to fight him tooth and nail."

It could make for some interesting racing over the next month. Hornish has run very well at tracks such as the 1.5-mile tri-oval at Kentucky Speedway, success Castroneves attributes to the way Hornish attacks the course.

"He likes to drive really on the edge, especially in the ovals, and at ovals it tends to be hard to do that," Castroneves said. "But there's no question he's a talented driver and we push each other a lot."

The winner may be whoever pushes back.

While some of the IRL tracks ¡ª such as Michigan ¡ª require teamwork to get to the front, tracks including the Kentucky Speedway allow for a little more individuality.

"It's a place where you can go on your own," said Castroneves, who has finished fifth three times in four starts at Kentucky. "It's about getting the right setup."

Hornish had the right setup three years ago, winning from the pole. He hasn't cracked the top five in two starts at the track for Penske. He finished 14th in 2004 and seventh last year.

Scott Sharp, a good friend of Castroneves who shared the inaugural IndyCar Series points title with Buzz Calkins in 1996, said it'll be interesting to see how the season plays out.

"More often than not, on two-car teams your biggest competitor is the guy next to you," Sharp said. "And it's easy to see that it could happen over there. There is a lot expected out of both of those guys ... but when it gets down to it, there can only be one champion and (each driver) wants to be the one."

Despite his close calls, Castroneves said he doesn't feel any added pressure to win the series. He knows he's got a good car, a good crew and a good chance. That's all he can ask for, well that and a fence to climb if he manages to hold onto the top spot after the checkered flag at the season-ending Peak Antifreeze Indy 300 at Chicagoland Speedway on Sept. 10.

"Trust me man, I can find any fence," he said with a laugh. "After winning the race, finding a fence is a good problem to have."