Greg Biffle was the fastest man on track on Friday as the NASCAR Sprint Cup drivers ran two practice sessions ahead of this weekend's CampingWorld.com 500.

The Roush Fenway Racing driver set the benchmark time of 47.597s (201.189mph) early in the first 55-minute session in the early afternoon on the 2.666-mile Talladega Superspeedway in Alabama, pipping Stewart-Haas Racing's Danica Patrick to the top spot on the timing screens by 0.134s

Meanwhile Penske's Brad Keselowski was fastest in the later practice when he posted a best time of 48.752s (196.423mph) to put himself ahead of fellow Ford contender Ryan Blaney in the Wood Brothers #21 part-time entry, which has a technical affiliation with the Penske team.

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CLICK: Full Friday practice times from Talladega.

Much of the early session was spent testing the aerodynamics and practicing drafting. HScott Motorsports' Justin Allgaier was third fastest ahead of Michael Waltrip Racing's Clint Bowyer in a surprising result that saw the entire 12-strong Chase field end up outside the top ten.

Of the championship contenders, the highest placed were Joe Gibbs Racing trio Matt Kenseth (13th), Denny Hamlin (15th), Carl Edwards (16th). The lowest were Furniture Row Racing's Martin Truex Jr. (31st) and Richard Childress Racing's Ryan Newman (32nd).

The later session saw participation from only two-thirds of the 45 cars entered in this weekend's race. Keselowski's time was set early in the session with a boost from stablemate Blaney. Dale Earnhardt Jr. (Hendrick Motorsports) was third fastest ahead of two more non-Chase names, SHR's Tony Stewart and Hendrick's Kasey Kahne.

Defending Sprint Cup champion Kevin Harvick was sixth, just ahead of SHR team mates Kurt Busch and Danica Patrick, with Hendrick pair Jimmie Johnson and Jeff Gordon rounding out the top ten. With only 30 cars taking part, speeds were slower as drivers worked more on single-car qualifying laps without the aerodynamic boost that they had enjoyed from running in numbers earlier in the day.

This weekend's race is the final restrictor plate event of the 2015 season. It's also the last race before a further four drivers are cut from Chase contention, leaving just eight remaining in the running for this year's championship.

Currently at risk of failing to make the cut for the Eliminator Round are Kyle Busch (JGR), Newman, Earnhardt and Kenseth.

Busch and Newman still have a chance of getting out of the drop zone with solid performances at Talladega - providing that one or more of the drivers above them have a bad day on Sunday afternoon.

Truex Jr. is on the bubble on 3070 points, just six points ahead of Busch. But there are three drivers tied just one point further ahead, with Harvick, Gordon and Keselowski all sitting on 3071 points and very much at risk if they get involved in an early accident or suffer a technical failure at Talladega.

Any of those at rick of being eliminated can claim a 'Get Out Of Jail Free' card if they win this weekend's race, which guarantees automatic progression.

Currently in this round of the Chase there has been only one race winner with Keselowski's team mate Joey Logano clinching victory at both Charlotte Motor Speedway and Kansas Speedway in the last two weeks.

Logano took the Kansas win in controversial circumstances when he spun long-time race leader Matt Kenseth out while the pair were battling for the lead in the final laps of the race.

Kenseth ended up finishing in 20th place after the incident which is what has put him bottom on the points standings and at risk of failing to make the cut - and it was clear on Friday that he was still seething at Logano's actions.

"Someday he might mature a little bit," said Kenseth, adding that the 25-year-old needed to "stop running his mouth" about the incident.

"He's lying when he said he didn't do it on purpose. He lifted the tyres off the ground, and he's too good a race car driver to do that by accident," Kenseth complained. "I did everything I could do to win the race. He drove himself into the wall twice.

"I wouldn't do anything different because I didn't do anything wrong," Kenseth added. "I did everything I was supposed to do."

However, Logano wasn't backing down in the row.

"I've had time to look at it, and truly I stay true to how I feel," Logano told FOX Sports at Talladega on Friday. "I don't think either one of us is sorry about how it happened. We were both racing hard. He was doing what he had to do. I don't blame him. I don't look bad at him for blocking.

"If I was in his shoes I'd probably do the same thing. If he was in my shoes, he'd probably do the same thing as well."

The prospect of an off-track feud leading to on-track reprisals looms large over this weekend's event. Talladega is a notorious 'crap shoot' with the possibility of one of the circuits infamous 'big ones' lurking around every lap with the potential to catch out literally anyone and everyone, and in the process ruin more than a few dreams of title glory.

Qualifying for this weekend's race is due to take place at 3.15pm local time (9.15pm BST) on Saturday following the Camping World Truck Series event, with the 188-lap, 500-mile Cup race itself due to get the green flag shortly after 1.30pm local time (5.30pm GMT) on Sunday afternoon.

See full NASCAR Sprint Cup Series practice times for the CampingWorld.com 500 from Talladega Superspeedway.

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