Las Vegas, NV (SportsNetwork.com) - After missing the 2013 Chase for the Sprint Cup championship, Brad Keselowski has all but guaranteed himself a berth in this year's playoffs by winning Sunday's Kobalt 400 in dramatic fashion at Las Vegas Motor Speedway.

Keselowski, the 2012 Sprint Cup Series champion, grabbed the lead from Dale Earnhardt Jr. on the final lap when Earnhardt ran out of fuel while coming out of turn 2. He claimed his 11th career victory in NASCAR's premier series. Keselowski also won Saturday's 300-mile Nationwide Series race for a weekend sweep at Las Vegas.

Starting second, Keselowski led the most laps with 53 but had an encounter with the wall just before the halfway point. It did not cause any significant damage to his No. 2 Team Penske Ford. Keselowski had also pitted out of sequence throughout the race. He benefited during the last caution with less than 50 laps to go when he was able to pit for the final time.

"Heck of a call [by crew chief Paul Wolfe] throughout the race to get us out front and get us some track position because clean air in these cars is so important," Keselowski said. "At the end, this car was just really fast, and I'm really proud of the team for giving me a car that was fast."

Keselowski became just the second driver to win both the Sprint Cup and Nationwide races at Las Vegas on the same weekend. Jeff Burton first did it in 2000.

Earnhardt opted not to pit during the final caution and took over the lead. He last pitted with 60 laps remaining. Earnhardt managed to coast across the finish line in the runner-up spot, 1.53 seconds behind Keselowski.

"We weren't going to run first or second had we not stayed out on that strategy," Earnhardt said. "We knew we were a lap short. We tried to save as much as we could. We got it to about half a lap, and it ran out off of [turn] 2. We took a gamble and didn't win the race, but it still worked in our favor to run second."

Earnhardt was attempting to win for the second time in three races this season. He won the Feb. 23 season-opening Daytona 500 and then finished second to Kevin Harvick last weekend at Phoenix.

"It sucks to lose like that, but we can't let that be a negative," Earnhardt added.

It was the 11th career Sprint Cup win for Keselowski, including his first at Las Vegas.

Last year, Keselowski became the second reigning Sprint Cup champion in the Chase era to miss the postseason. Tony Stewart failed to qualify for the Chase in 2006 after winning the title in the previous season. Keselowski finished 14th in the point standings and scored only one victory in the series last season, which came in the fall race at Charlotte.

During the offseason, NASCAR made sweeping changes to the Chase format by expanding the field of drivers/teams from 12 to 16. The top-15 drivers with the most wins over the first 26 races will become eligible for the playoffs, provided they have finished in the top-30 in points. The 16th and final position will go to the driver who is the highest in points without a victory.

"It's very special to get a win early in the year when it's just such a reliever for everyone on the team, myself included, to get that win in early and be able to enjoy the races and opportunities that we have instead of being stressed out about them," Keselowski said.

After finishing third, Paul Menard was quick to fly back home to North Carolina where his wife, Jennifer, is due to deliver their first child. Reigning Camping World Truck Series champion Matt Crafton was on standby if Menard needed to return home earlier.

Joey Logano, the pole sitter, took the fourth spot, followed by Carl Edwards and Jimmie Johnson, the six-time and defending series champion.

Ryan Newman, Kasey Kahne, Jeff Gordon and Matt Kenseth, who won this race one year ago, completed the top-10.

This year's 400-mile event at Las Vegas ran at a record pace of 154.633 mph and was completed in 2 hours and 35 minutes. There were just four cautions -- the first for fluid on the track, coming from Josh Wise's blown engine, and the other three for debris. All but one of the 43 drivers finished the race. Michael McDowell retired early due to engine failure.

One week after his win at Phoenix, Harvick suffered a broken left-front wheel hub, which required him to spend a short period of time in the garage for repairs. He ended up finishing 41st. Harvick is in his first season as driver of the No. 4 Chevrolet for Stewart-Haas Racing.

"Just a little parts failure there, and we'll figure out the cause of it and try to just keep that from happening," Harvick said. "Every week is a new notebook for us. I really think as we get established and get some foundation for our set-ups and just the little things this team is going to be dangerous."

On Thursday, teams test at Las Vegas to familiarize themselves with NASCAR's new rules package for intermediate tracks on the Sprint Cup schedule. Las Vegas was the first of 11 races on 1.5-mile tracks this season.