It was the proper play to call, it was executed perfectly, it produced the desired result. But it didn't count, and Buffalo lost its best chance to reach the AFC championship game.

Coach Chuck Knox wouldn't admit the delay-of-game penalty, that nullified a first down on the Cincinnati 11-yard line with about three minutes to play, was the reason his Bills were beaten by the Bengals, 28-21, today in an AFC semifinal at Riverfront Stadium. But some said it was his fist that put a hole in the dressing-room blackboard.

Knox preferred to talk about field position, turnovers, injuries and the flawless play of the Bengals, who didn't fumble or have an interception. However, the players involved in the inexcusable penalty admitted it could have cost them a trip to the Super Bowl.

"That was the damn game," said center Will Grant, who has the responsibility to watch the 30-second clock at the end of the field. "It seems awfully strange, the way it was called so late. Nobody was expecting it. Usually they throw the flag right away, but this time there was no whistle or anything until we had the first down."

What made the penalty so baffling was that it followed a timeout, when quarterback Joe Ferguson had the opportunity to talk with Knox about the play. He didn't have to wait in the huddle for it to be sent in.

"We took a timeout to talk over the play we wanted," Knox said. "Once we decided, we didn't change anything. I guess we just took too much time getting it off, according to an official."

The situation was fourth down and three at the Cincinnati 20, with the Bills trailing, 28-21. The play was for the fullback to delay out of the backfield, isolate on a linebacker and break to the sideline.

With about 22 seconds left on the 30-second clock, Knox substituted Ron Jessie for Mark Brammer at tight end and Lou Piccone, a wide receiver, for fullback Curtis Brown.

"We always send our subs in late, after the defense is set," Knox said. "These guys are better receivers, so we wanted them in there."

Ferguson said he was a little surprised to see the substitutes come in so late, but didn't think much of it because Knox had done it before. He said he didn't feel rushed or any need to hurry.

"There was about 22 seconds left when the players came in," said Grant. "About 15 when we broke the huddle and 12 when I looked at the clock for the last time before putting my head down. That's when Joe started his cadence. That's usually plenty of time."

Ferguson, a nine-year veteran, at first said there were 11 seconds remaining when he started barking signals, but later admitted that someone told him that.

"To be honest, I didn't look at the clock," Ferguson said. "I usually do, but nobody said to hurry and I wanted to try to read the presnap coverage. There was a lot of noise and I had to emphasize each number to both sides of the line, but I thought we had plenty of time.

"The play worked just the way we wanted. Lou isolated on the linebacker and got open near the sideline, and I got the ball to him. I thought we had a first down."

Instead it was fourth and eight and Ferguson overthrew Roland Hooks, who had a step on his defender, in the end zone. The Bengals took over and ran the clock down to 36 seconds before Pat McInally punted 60 yards to the Buffalo end zone.

"The coverage was set up the way we wanted," Ferguson said of his fourth-down misfire. "Hooks was on a linebacker, but the linebackers dropped deep and I had to throw long and hope he could get it."

That wasn't Ferguson's first poorly thrown pass. He completed only 15 of 31 and was intercepted by cornerback Ken Riley on Buffalo's second possession and by linebacker Bo Harris late in the second quarter.

"I felt I was letting a lot of people down," Ferguson said. "But I thought we came back after falling behind 14-0 and played well. After we tied it at 21, I thought we had the momentum, but Cincinnati kept moving the ball and eating up the clock."

Surprisingly, Ferguson said the loss of leading ground gainer Joe Cribbs (90 yards in 15 carries), when he strained a knee ligament on his 44-yard touchdown run in the third quarter, didn't hurt the Bills.

"By the time Joe got hurt, we were in a situation where we had to throw, anyway," Ferguson said. "We can't blame it on that. What makes it (the loss) so hard to accept is because it (the delay penalty) was a mistake. Something we could have prevented."