It was late in game three of the National Basketball Association championship series and Seattle's Dennis Johnson had just blocked another Kevin Grevey jump shot.

"Hey, Dennis," said Grevey, the good-humored Bullet guard. "Don't do that to me on national television. My parents are watching and so is my younger brother. He's going to get discouraged about pursuing a basketball career if you keep that up."

Johnson laughed, but he didn't ease up on defense. Nor did he curb his point production at the other end. Johnson, after four games, is this series' most valuable player.

In tying the final round at two wins apiece. Washington has solved all of Seattle's riddles except one: Dennis Johnson. The Bullets feel that if they can just neutralize him to some extent, they can win the NBA title, which seemed all but unobtainable after they lost at home in game three. But Grevey says stopping Johnson will be a most difficult chore.

"He hasn't got an ego problem," said Grevey. "He plays within himself. He doesn't need to be flashy or put on one-on-one shows.It's tough to rattle him."

Johnson is coming off a superb series against Denver's David Thompson. Many Washington players feel Johnson is the difference between the series being tied and the Bullets having at least a 3-1 edge.

Almost singlehandedly, he has dominated the Bullet guards. His 13 blocks - most by anyone in the series - have caused Washington's guards to think about their shots and alter their strategy. He has had the ability to come up with important plays just when Seattle needs help.

His seven blocks in game three were a major reason the Washington guards were ineffective, making only nine of 45 shots. Then, in game four Tuesday night, when Bobby Dandridge was trying to win it in regulation with a baseline jumper, Johnson made a marvelous play, leaping over teammate John Johnson to swat away the ball.

He's got that baby face, but he's a killer inside," said Bullet Coach Dick Motta. "He's deceiving. He can hurt you in so many ways. I know he is giving us fits."

Grevey readily admits that Johnson has forced him out of his normal offensive approach. Tired of having jump shots knocked back into the face. Grevey began driving more Tuesday night. He had 17 points before a hip pointer forced him to the sideline.

"I'm not too proud to change," said Grevey, who hurt the hip on the game's third play, but said yesterday he will be able to play in game five tomorrow night.

"Why keep forcing things when you know the man is going to toss it back in your face? I'd rather come off screens and shoot the jumper but he is charging my left side and overplaying me.

"He's so aggressive that he's easy to drive by. That's why I can get inside of him. I'm not the best penetrator in the league but I had to come up with a way to handle him."

Grevey didn't have quite as much respect for Johnson earlier in the series. He scored 27 points in the opener, off a combination of jumpers and layups, and Johnson admitted afterward he had to "make some adjustments. Grevey surprised me."

Now Grevey says Johnson "may be the toughest player in the league for me to score against. He has such long arms. They are like the arms of a guy 6-8. He doesn't jump into you. He waits for you to go up and then he uses those arms to get you."

Motta claims Johnson, in only his second pro season, "is already one of the best guards in the league, and not just defensively. He showed that against Thompson and he's showing us."

What has surprised the Bullets is Johnson's offense. He had 21 points in game two and a career-high 33 Tuesday night, giving Motta and his assistant coach, Bernie Bickerstaff, a headache they didn't expect.

"We thought Freddy Brown and Gus Williams would score," said Bickerstaff. "But Johnson is more consistent than either one of them.

"We've got to make him stick it from the outside. All he is doing is driving to his left and getting uncontested layups when he gets by the guards.

"We've got to make up our minds that we can't help out on anyone else and leave their guards alone, because those guards can shoot the ball."

To offset Johnson. Washington began moving the ball upcourt more quickly in the second half Tuesday, trying to set up the offense before the Seattle guard could make the transition to defense. And the Bullet guards are trying to shoot faster, so Johnson won't be able to race across court, as he has been doing, and block shots.

Motta admits that Johnson's defense has had such a psychological affect on his club that even his reserves have been bothered. Until game four, two of the major substitutes, Charles Johnson and Larry Wright, had contributed little after getting an early taste of Johnson's shot blocking.

And when Wright and Johnson finally found their shooting touch in the fourth period Tuesday night, it was partly because they didn't have to contend with Johnson. He was sitting on the bench with three fouls while Williams and Brown were trying to carry the scoring load.

"That's the combination we'd like to see them use," said Bickerstaff. "They aren't as effective with Dennis out of the lineup. When we've played well, he's been on the bench."

Few could have predicted five years ago that Dennis Johnson, one of 16 children, would be such a factor in the NBA's premier event.

He had such an undistinguished high school basketball career that he drove a fork lift for a year after graduation before deciding to attend a junior college. Then he played for Pepperdine, the small religious college in Malibu, Calif., and earned a reputation as one of the best defensive guards on the West Coast.

The Sonics gambled last year when they drafted him as their second choice on the second round. His college class had graduated, so he was eligible for the draft although he could play another year at Pepperdine. He decided to start his pro career early and wound up averaging 20 minutes a game as a rookie.

"I've still got a lot to learn about the game," said Johnson. "But I didn't think another year in college would help me. I've got no regrets, none at all. If I had played another year, I probably wouldn't have been with Seattle."

Johnson admits he was bolstered by his performance against Thompson, the Nuggets' $5 million all-purpose player. Although Johnson was not selected to the all-league defensive team, he figured if he could control Thompson, he could handle almost anyone.

"I've really never blocked shots quite like I have in this series," he said. "Never seen in one game, anywhere. But they kept challenging me and jumping into me. They made it easy for me."

Johnson's easy-going manner - he complains only about referee's calls - has helped him handle the increasing pressures that his new-found fame have brought. Grevey says you couldn't ask for a nicer person to block your shot.

"He's a fine guy," said Grevey. "We are always talking out there about how the game is going. There is not a hate relationship, not by any means. He's playing as hard as he can and I'm trying to do the same."

Then Grevey laughed. "But I just wish he would have one off game," he said. It would be nice to see if I could make an uncontested jumper again."