Morelos failed to convert an easy chance for Rangers from just yards out in the final minutes of the Scottish Premiership game between the Gers and Celtic at the weekend.
Celtic won the Old Firm derby against Rangers 3-2 on Sunday afternoon despite playing for most of the second half with just 10 men.
Bain, who started in goal for the Hoops and was actually making his debut for the Glasgow giants since his loan move from Dundee in the January transfer window, has admitted that he did not expect Rangers striker Morelos to miss.
The 26-year-old Celtic goalkeeper told The Scotsman about Morelos: “I’d saved the first shot and I looked up and saw the ball going to him.
“I just thought, ‘Aw naw’. Then luckily he has hit the post and I was able to scramble and catch it before it went over the line.
“I was expecting him to score but I knew I had to get up just in case anything happened. Luckily for me, it hit the post and rolled along the line.”
Morelos joined Rangers from HJK Helsinki in the summer of 2017 for a transfer fee reported by Sky Sports to be worth £1.5 million.
The Colombian striker is one of the best players in the Scottish Premiership and has been playing well for the Gers so far this season.
The 21-year-old has scored 13 goals and provided five assists in 28 Scottish Premiership matches for Rangers so far this campaign, according to Transfermarkt.co.uk.