Four races down, six to go to determine the 2006 Nextel Cup champion.

Last week the Roush Racing team was dominant, placing four of its drivers in the top-five. Unfortunately for Roush and the other "Chase" teams, the fifth driver was Tony Stewart.

Over the next six races, it is likely to be more of the same since four of the remaining events will be held on mile-and-a-half ovals similar to last week's event at the Kansas Speedway.

The question is can any of Roush Racing's drivers make the leap back into contention?

Greg Biffle is the highest ranked Roush driver, 88 points behind Stewart following his second-place finish in Kansas.

"I tell you what, it was a great run for our National Guard car," said Biffle after the race. "The thing ran flawless all day. I'll finish second to Mark Martin any day of the week. He drove his butt off out there and made two tires work."

Carl Edwards is just 95 points back, Martin is 113 points behind and 2003 Nextel Cup champion Matt Kenseth trails by 116 points.

Stewart continued what he did in the Nextel Cup "regular" season producing his 15th top-10 in the last 16 races (including five wins) to expand his lead to 75 points over his nearest rival Ryan Newman.

If Stewart continues his fantastic run of top-10 finishes, no one is going to catch him.

But there is some hope.

In races on 1.5-mile ovals this season, Stewart has not been particularly good. In six starts on mile-and-a-half ovals, Stewart's average finish is 15.16 including a 24th-place result at the Lowe's Motor Speedway in May. The last six races include a race in Texas (where Stewart finished 31st) and Atlanta (Stewart was 17th).

So there is still a glimmer of hope for the other "Chase" drivers. But there can be no more slip ups. To catch Stewart, a driver will need to be almost perfect down the stretch. Maybe not like Jimmie Johnson circa 2004, but close.

If anyone can go on a streak like that in 2005 it will be Biffle.

The No.16 National Guard Ford has been very fast all season. He began the season with five wins in the first 15 events and has been a driver to be watched all season. He won at Texas, finished third in Atlanta and was sixth in the Coca-Cola 600 in Charlotte.

Look for Biffle to have another big race at the Lowe's Motor Speedway this weekend and make a big run at Stewart for the championship.