Celtic had goalkeeper Fraser Forster to thank as they withstood heavy pressure to beat Glasgow rivals Rangers 1-0 in the Scottish League Cup final on Sunday to make it 10 consecutive domestic trophies in a row.
The game appeared to swing back into Rangers' favour just three minutes later when Jeremie Frimpong gave away a penalty and was red-carded following a shove on Morelos.
However, the Colombia international saw his spot kick saved by Forster and 10-man Celtic held on to win the trophy for the fifth time in six seasons.
Mikey Johnston then had a chance to double Celtic's lead as the Hoops caught Rangers on the counterattack and he was played clean through but skewed his effort wide. Morelos had a golden chance to equalise in stoppage time, but fired wide.
Forster told BBC Sport after the match: "As long as you win, that's all that matters. We really had to fight and grind it out. It was just one of them days, it went my way today. I'm buzzing.
"There's been days when it's not gone my way, today it has. I can't say how much it means to me. I didn't really think about the penalty to be honest. I picked the way it went. I'll take it.
"That's why I came back; to play in games like this -- to win silverware, to play European football."
The result means Celtic have won every single trophy available domestically since the 2016-17 League Cup, with captain Scott Brown having claimed his 20th major honour.