Wellings netted her 40th goal of the season with a spot-kick that put Celtic 2-1 up in the opening half. City came back to restore parity a second time before Izzy Atkinson scored the winner.
Wellings, though, gave an insight into the sledging that went on in one of the high pressure moments of her career.
“I was standing on the spot for a while and the girls were trying to put me off,” she said. “They were saying ‘Don’t miss, don’t miss.’ I said ‘don’t worry, just go away and I’ll put it right in the back of net’.
“I don’t really get nervous. I just wanted to take it and score it!”
Fran Alonso, the Celtic women’s manager, described it as the best moment of his football career.
“This day is my best day in football, without a doubt,” he said.
“It was an exciting game until the end and what a support for both teams. For us, with a player sent off that support made up for it when we needed. Even with ten men we kept going for it and creating chances. We did not settle for a draw or want the game to go to penalties.
“We had to do more running and we never stopped believing. I am delighted. It was perfect. I wouldn’t change a single thing about this season.”
Glasgow City manager Eileen Gleeson did not want to comment after the game. The players were still in the dressing room more than an hour after the trophy presentation with captain Hayley Lauder forced to front up in the aftermath of the defeat and a trophyless season – the club’s first in 18 years.
“We didn’t deserve anything more than what we have got this season,” she said. “It is a long six weeks now but it is a chance for us to reflect and think about where we need to be better.
“It is very hard just now. It was a quiet dressing room, an emotional dressing room, as you can imagine.”