Welcome to the RealClearSports Weekend Warmup!

Are you ready for some football?

In a stunning upset, the Super Bowl champion New England Patriots lost the opening game of the season last night to the Kansas City Chiefs, 42-27, and just like that the craziness of the National Football League is back in our lives.

Get up to speed with everything you need to know about the NFL with our Top 10 NFL Storylines and the Top 10 Contenders for 2017.

NFL

The Sunday's action features several zesty matchups to get you right back in the swing of things. A pair of playoff hopefuls look to start the season on the right foot in Nashville as Marcus Mariota and the Titans host Derek Carr's Raiders (1 p.m. ET on CBS). And in the NFC East, the Philadelphia Eagles face the Washington Redskins (1 p.m. ET on Fox).

The premier matchup on Sunday features the vaunted Seattle Seahawks' defense facing off against the amazing Aaron Rodgers Green Bay Packers offense (4:25 p.m. ET on Fox). And stick around for prime-time matchup of Giants at Cowboys (8:30 p.m. ET on NBC).

And, it isn't the weekend, but we can't deny we're excited about a Monday night double-header of Saints at Vikings (7:10 p.m. ET on ESPN) followed by Chargers at Broncos (10:20 p.m. ET on ESPN).

College Football

Another weekend in college football, another college football bonanza. And if the opening weekend is any indication, we're in for a wild year of gridiron action filled with upsets and intrigue.

Saturday night's fireworks start with No. 3 Clemson taking on No. 13 Auburn (7 p.m. ET on ESPN). Just 30 minutes after that opening whistle, No. 15 Georgia will test out its new freshman sensation QB, Jake Fromm, against No. 24 Notre Dame in South Bend, Ind. (7:30 p.m. ET NBC).

The College GameDay crew will be in Columbus, Ohio, for a gripping contest between two of college football's most talented programs. No. 2 Ohio State hosts No. 5 Oklahoma, pitting the Buckeyes' bevy of blue-chip talent on defense against Heisman Trophy hopeful Baker Mayfield and the Sooners (7: 30 p.m. ET on ABC).

Not to be forgotten, the West Coast features two exciting matchups with potential playoff implications as well. No. 14 Stanford heads south to play No. 6 USC (8:30 p.m. ET on Fox). And then stay up late for Boise State's trip to Pullman to face eclectic Mike Leach and his No. 20 Washington State Cougars (10:30 p.m. ET on ESPN).

U.S. Open

We missed out on the dream matchup of Roger Federer vs. Rafael Nadal, but the run of Juan Martin del Potro may have been worth it all. Friday is semifinal night (coverage on ESPN 4-11 p.m. ET) with Nadal facing off against del Potro and Kevin Anderson taking on Pablo Carreño Busta. (The winners play Sunday, 4 p.m. on ESPN.)

On the women's side we got an all-American final with Sloane Stephens vs. Madison Keys, they'll face off Saturday (4 p.m. ET on ESPN).

MLB

It is not as if the final month of the season needed any extra spice, but we got some after MLB busted the Red Sox for sign stealing against the Yankees. Friday night those Yankees face the Rangers (8 p.m. ET on MLB Network).

The hottest team in baseball, the Cleveland Indians, rattled off a 15-game win streak to put them in contention for the best record in the American League. They host Baltimore for a three-game set against the Orioles. (You can see them Saturday at 1 p.m. ET on Fox and Sunday night at 8 p.m. ET on ESPN.)

And for those who would like a little change of pace on NFL Sunday, the slumping Dodgers, who have lost 12 of 13, host the Colorado Rockies (4 p.m. ET on TBS).

Soccer

Start your weekend off bright and early with what looks to be an explosive match in the Premier League when Liverpool travels to play Manchester City (7:30 a.m. ET on NBCSN). And over in the Bundesliga, Freiburg faces Borussia Dortmund (9:30 a.m. ET on FS1).

In MLS, a Sunday triple-header features the Columbus Crew taking on Sporting Kansas City (1 p.m. ET on ESPN), Atlanta United against FC Dallas (3:30 p.m. ET on FS1), and Western Conference foes LA Galaxy at Seattle Sounders (9 p.m. ET on FS1).

On This Day

On this date in 1968, Arthur Ashe defeated Tom Okker (14-12, 5-7, 6-3, 3-6, 6-3) to become the first African-American man to win the U.S. Open. Ashe also became the first player to win both the amateur and open national championships in the same year. And in order to maintain Davis Cup eligibility, Ashe had to maintain his amateur status and couldn't accept the $14,000 first-prize money. Instead he received just $20 daily expenses.

Check RealClearSports.com throughout the weekend for coverage of the NFL's opening Sunday, college football, MLB, and much more. Follow us on Twitter @RealClearSports and join the conversation on Facebook.