The man who broke Killie's hearts in the 57 final replay admits he was gripped by fear in the first Hampden match.
Luckily for the keeper he played a blinder second time around as the Bairns won 2-1.
Now he hopes that Alex Totten's battlers keep their cool tomorrow - and seize their chance in the Ibrox shootout.
He said: "The best thing the players can do is remember they are just playing another game of football.
"The pitch still has a goal at either end and the match is played on grass.
"Unfortunately our first final passed in a flash and it was over before I came to terms with it.
"Luckily for me it went to a replay and by then I was able to treat it as a game rather than a huge occasion.
"I was only 20 at the time and it was a big lesson to me. But I don't think there is another manager who will be better than Alex Totten at reminding his players to keep a level head.
"We both played under Bill Shankly at Liverpool in the 60s and his message was always very straightforward - do the simple things and pass the ball quickly.
"Alex will have his players doing exactly that and if they keep calm they can win the cup."
Slater went on to play in the Dundee side who won the league and played in the Dark Blues' famous European Cup run which was only ended by eventual winners AC Milan in the semi- final.
He also starred in the 64 cup final defeat by Rangers before moving to Anfield.
But he'll always be remembered in Kilmarnock as the man who prevented the cup going to Rugby Park 40 years ago.
Slater recalled: "Early on in the first game I was ushering a ball past the post - except it hit it and came back into play.
"I remember one of the defenders saying something like `Oh my God' before giving me a real blast.
"Fortunately my concentration was better in the second game than it was in the first."
Yesterday Slater met some of the Killie team he frustrated in a 57 Hampden reunion.
Ralph Collins, who skipper Killie that day, confessed: "We always felt we would have won the trophy if it hadn't been for that so- and-so keeper.
"I'm just hoping Bobby Williamson can get it right for Kilmarnock this time and leads them to victory."