When Brock Lesnar stepped into the ring Sunday night to take the WWE World Heavyweight championship from John Cena after a brutal beating, it was the biggest wrestling match of 2014. More than that, it continued a legacy that began in hallowed Madison Square Garden, a journey that has spanned 18 different arenas and 26 years. It, once again, established SummerSlam as one of the WWE's truly marque events.

In the beginning there were four. 

The first regular WWE pay-per-view, of course, was WrestleMania. The granddaddy of them all, the showcase of the immortals, it requires no explanation. Survivor Series was next, a fall classic conceived as a middle finger to rival Jim Crockett's Starrcade in 1987. The Royal Rumble followed, a television special initially created to stomp a mudhole in Crockett's second pay-per-view offering.

And then there was SummerSlam.

Designed as a summer-time spectacular, Vince McMahon went big in the initial offering. There were four men in the main event, each a legitimate icon in his own right: Hulk Hogan, Randy Savage, The Million Dollar Man and Andre the Giant. Those are names that demand celebration in song, legends who redefined their industry, men who were writing wrestling history with every leg drop and maniacal laugh. 

While, each year since the show has presented a compelling main event match, the company has yet to reach the heights of that initial offering.

Until now. 

John Cena, simply put, is the Hulk Hogan of his era. Despised by many hardcore fans, he has nevertheless emerged from the promotional morass as a needle-mover and merchandising maven. That he's also a razor-sharp worker, capable as any man in WWE to raise wrestling from its carnival roots into the realm of art, is a secret many have not yet discovered.

Lesnar, a former UFC champion, is perhaps an even bigger star. After his name moved millions of pay-per-view units as a UFC fighter, Lesnar returned to WWE an even bigger star than when he departed. In the modern age, only the Rock can say the same.

More than that, he was the one wrestling star who provided WWE something even better than money—athletic credibility. That's why he was the only man who could end the Undertaker's streak. It's why, despite his limited schedule, he left Los Angeles with the WWE title as well.

On paper it was an even match. In the ring it was a blowout—but a compelling one. Cena never knew what hit him. Sixteen German suplexes rattled his brain and an F5 finished things for good.

Let the Brock Lesnar era officially begin.

Of course, one match does not a card make. Luckily for WWE fans, the action throughout the night delivered in a major way. Even the grudge match between Stephanie McMahon and Brie Bella was an unexpected joy. It was that kind of night. 

What follows is our trademark instant analysis and letter grades for every bout on the show. Matches are graded not just in comparison to each other, but based on how well they live up to their potential and to fans' expectations. Disagree with our assessments? Feel free to sound off in the comments.