The gesture was not one of poor grace, merely frustration following the 0-0 draw which sent his side out of the Uefa Cup on the away-goals rule. For Donnelly, though, the compensation is that he has another shirt coming to his collection: this time, the dark blue of Scotland.
The 22-year-old striker has already won two caps for his country, but those were as substitutes in meaningless friendlies with Wales and Malta at the end of last season. Now Craig Brown has earmarked Donnelly to start Saturday's World Cup qualifying tie with Latvia, which could rubber-stamp the Scots' passport for France '98.
Not bad for a player who was not even sure of a place on the Celtic bench in July when a rollercoaster season started for both himself and his club. The exit of those in his path - Jorge Cadete and Paolo di Canio - and Darren Jackson's unforeseen medical problem forced everyone, from coach Wim Jansen to the fans, to focus on Donnelly.
He was the kid who, when he exploded on to the Celtic scene in 1994 with a flurry of goals, was unfortunately labelled the new Kenny Dalglish by the then-manager Lou Macari. Two goals at Old Trafford in a testimonial for Mark Hughes seemed to back up that judgement but then Donnelly went a year without scoring and eventually found the only way to get a game was by playing out of position on the right wing. Even that option was closed down when Celtic bought di Canio in the summer of 1996.
It has taken him this long to come back to where he started, with the No 9 shirt on his back. Roy Evans, the Liverpool manager, picked Donnelly out before a ball had even been kicked as Celtic's chief threat, and was vindicated over 180 minutes. The young Celt scored one of his eight goals this term and was denied another by the crossbar.
That was why Merseyside in midweek didn't mark the end for Donnelly, merely the end of the beginning. The Scotland coach Brown, explaining why he had called him in for the Latvia game, said: "Simon matured a lot in the last year and is a very intelligent player right now."
That presumably will earn Donnelly a place alongside Kevin Gallacher in front of a sellout 50,000 crowd on his own Celtic Park pitch next week. It was the role Jackson fulfilled until his brain surgery last month. "The only reason I got my chance was because of the injury to Tommy Johnson and then Darren's problem. Now I'm just taking my chance and trying to show that I can play there.
"This was a big season for me. I'd got a taste of the Scotland thing last season and I want to make my mark," he said with the hunger of a player who knows he is making up for lost time. "Well, I've been in the Celtic side for three years now and people can't keep saying that I'm merely a prospect. I can't keep falling back on that as an excuse either, I need to move on.
"I feel I can play as either a striker or a midfielder. After I had my goal drought, Tommy Burns moved me about to take the pressure off me. Then the club bought Pierre van Hooijdonk, so I played out wide in the 1995-96 season, when we lost just one game, and built up a good relationship with Jackie McNamara. Then Paolo came and I didn't play so much last season."
The praise of Evans, who noted that home-grown strikers suffer most in this big-buy era, has fed Donnelly's confidence. "It boosts you when someone who is so respected when it comes to strikers says that about you. I love to read things like that but it's also important not to get carried away. A striker is only as good as his last game."
Talking of which, Donnelly will not be brooding in the build-up to Latvia about his miss at Anfield after David James dropped the ball at his feet. "A striker has to be prepared to miss," he said, "and simply concentrate on the next one - because there will always be another chance around the corner."