The Steelmen – fourth in the Premiership – had started the game as firm favourites to see off a team sitting eighth in the Championship.
But it proved to be anything but straightforward for the hosts as – despite dominating the 90 minutes – they couldn’t break down a stuffy Morton side who forced extra time at 0-0 after ’Well had failed to take one of several scoring chances.
And the hosts fell behind to Robbie Muirhead’s fine curled effort right at the end of the first extra time period, before Dutch ace Kevin van Veen equalised from a penalty after Michael Ledger fouled debutant Ross Tierney and Liam Donnelly smashed home a stunning late winner.
“It was about perseverance,” said Alexander. “When Morton got that goal, it put us in a difficult spot but credit to the players for battling back. It was a fantastic penalty from Kevin and a great finish from Liam.
“It was about how long we had left to come back and we didn’t have that long. We had 15 minutes and we hadn’t managed to get that goal in the previous 105 minutes so we knew time was against us.
“We asked the players not to panic in extra time half-time because we felt that we would have that extra bit of quality to at least get an equaliser and maybe a winner and we’ve done both.
“I am always confident in my players. It was a typical cup tie.
“I thought we played well and created a lot of chances.
"We dominated but we knew Morton were a well-coached, organised, and motivated team who were going to be hard to break down and they were exactly that.
“But I felt we just couldn’t find that final touch and their keeper (Jack Hamilton) made some excellent saves.”
’Well fans will hope that beating Morton is a positive omen as they also saw off the Greenock side on their way to winning the 1991 Scottish Cup, which remains their last major honour.
That unforgettable campaign 31 years ago started with a win over Aberdeen, ’Well’s next cup opponents at Fir Park in round five on the weekend of February 12.