There is one thing that Redskins offensive tackle Joe Jacoby would like understood from the start. He is not a gentle giant. He would like it known that he is just as mean and just as physical as Lyle Alzado, the vaunted Los Angeles Raiders defensive end he will be matched against Sunday at RFK Stadium.

Lots of interesting facts surround this game. These are two of the teams with the best records in the NFL, the Redskins having won 23 of their last 28 and the Raiders 13 of their last 15, including all four this year.

The Raiders are one of the most physical teams in the league, and the Redskins have never beaten them, having lost each of their three meetings--the last time in 1980.

The focus Sunday will be on runners John Riggins and Marcus Allen, and quarterbacks Joe Theismann and Jim Plunkett. But the outcome probably depends as much on what Jacoby and Alzado do as on anything else.

Alzado has the reputation, but that doesn't bother Jacoby, who shows little emotion during the week, but acts differently once the game starts.

"On the field, Joe is as mean as he can be," said Redskins line coach Joe Bugel, "and I can't think of a better matchup than him against Alzado.

"Joe is going to have to play 60 minutes of tough nose football because Alzado will probably be the strongest guy Joe will play against and he keeps coming play after play after play."

The Raiders weren't pressed in any of their first four games and have recorded 17 sacks, five of them by Alzado.

At 34, the 6-foot-3 and 260-pound Alzado is as quick and strong as ever. But Jacoby, 26, is 6-7 and 298 and one of the premier tackles in the NFL. He isn't worried.

"I'm glad Joe has had four warmups," said Bugel. "He's ready for Alzado. He knows what he has to do to get the job done and he's intelligent enough to do it. I think Alzado is too old to be scared and he isn't going to change his style any. It's just going to be a battle. Although Alzado, who once fought Muhammad Ali, has the reputation of being mean and dirty, Jacoby said it isn't true.

"He's just a 100 percenter," Jacoby said. "He'll do anything he can to get at the quarterback. I've watched a lot of film on him. He's just physical. He won't back off.

"I started thinking about him Monday, but I won't get really psyched up until game time. The thing to do is go through the week preparing yourself by concentrating in practice. You can't stay psyched up that long, so you have to get yourself ready and get physical on game day."

While Jacoby says "90 percent of the game is intelligence," Alzado says he has always "approached the game in a physical sense. I keep going after my man until I know I have him. I don't give up. I try to wear him down physically. I don't showboat and I don't blow smoke. I am what I am and I do what I have to do."

Bugel said that as vicious as he expects the Alzado-Jacoby matchup to be, it won't be the only one.

"It's going to be two physical teams going toe-to-toe," he said. "It's the heavyweight championship of the world." Said Coach Joe Gibbs, "The Raiders are big and physical and they manhandle people up front."

Not if Jacoby can help it.