This week could be the biggest in Rob Van Dam’s career. For Rey Mysterio, it could be one of the toughest. Sunday night, RVD will cash in his Money in the Bank briefcase and challenge John Cena for the WWE Championship at ECW One Night Stand, while Mysterio will defend the World Heavyweight Championship against Sabu. But four days before ECW One Night Stand, RVD and Mysterio will have to face each other at WWE vs. ECW Head to Head tonight. In fact, their match will kick the show off right at 9/8 CT on the USA Network.

The two men have a long history, having first met when both were in ECW a decade ago. They later became good friends and partners on SmackDown, winning the World Tag Team Championship in late-2004. However, this will be the first time that the two have locked horns against each other.

Despite the fact that the match with Rey is less than a week away from the biggest match of his career, Rob is looking forward to facing his good friend and former tag team partner. “We had a lot of success as a tag team on SmackDown, which was great,” Rob told WWE.com. “I love Rey Rey and there’s nothing personal going into this match. A lot of people say I’m one of the most gifted athletes in WWE, but Rey is right there as well. He’s awesome and I love watching him.”

And even with his gold on the line Sunday, Mysterio is also eagerly awaiting tonight. “I’ve had to face several former partners before; Edge, Eddie Guerrero and now Rob,” he told WWE.com. “We got along well as partners because our styles are so similar, and because of that I think we can go out there and give the fans something special. They know what we bring to the table, a great blend of extreme wrestling and the lucha libre style. It should be an awesome match.”

Of course, being in there with a good friend doesn’t mean RVD’s desire to win is any less. “I’m going to do whatever it takes to come out on top. Rey doesn’t quite have the kicking power I do, so maybe I’ll use that to my advantage. Whatever happens, the fans are the real winners.”

And despite the chaos of the contract signing Monday night on RAW, RVD says there’s no animosity heading into One Night Stand either. “I like John, he’s a fighting champion and we’ve been on the same side,” RVD said, “but I’m going to give him the fight of his life on Sunday. I have nothing personal against him, but there isn’t a greater opportunity for me to cash in than One Night Stand. The ECW atmosphere is by far my most comfortable surroundings, and it’s where I’m at my best.”

After watching what happened to John Cena on RAW, however, does Mysterio think the same fate might await him tonight? “I hope not,” he said. “I know there’s a lot of history with Rob and Sabu in ECW. But I was part of ECW once, and the locker room atmosphere was great. We were all one big family, so I’m hoping that I won’t have to watch my back. I think the ECW locker room can respect me for what I have accomplished and leave Rob and I to steal the show.”

Come Monday morning, Rey Mysterio and Rob Van Dam could be the World Heavyweight and WWE Champions respectively. And depending on what happens tonight, they’ll hopefully still be friends as well.