Twelve years into the reign of Jock Stein, season 1976/77 was turning out to be a most interesting one.
On the debit side, the team had lost 1-2 to Aberdeen after extra-time in the final of the League Cup and had made a surprise first-round exit in the UEFA Cup at the hands of the little-known Wisla Krakow of Poland. However, at the beginning of March the league campaign was going well, with Celtic seven points clear of Rangers and the Scottish Cup results had been to the liking of the support.
In the third round, Celtic had disposed of Airdrie ( 5-0 after a 1-1 draw) then drew again, this time with Ayr United (1-1) at Celtic Park in round four. And that, of course, meant a replay, which was held on this day in 1977 down at Somerset Park.
The Celtic side on the night – Latchford, McGrain, Lynch, Stanton, McDonald, Aitken, Doyle, Glavin, Craig, Dalglish and Wilson – were up for the occasion and took an early lead in seven minutes thanks to a penalty by Ronnie Glavin.
The crowd of just over 13,000 then saw Masterton pull one back for the Honest Men in 23 minutes but two further goals in the second half by Johnny Doyle (47) and Roy Aitken (63) put Celtic into the quarter-finals, where they would meet Queen of the South.
NB. In the Ayr United side that night was a future Celt. Joe Filippi signed for the Hoops in November 1977 and made 42 appearances for the club over the following two years.