Watson, who operates as a holding midfielder, rarely goes forward for corners.
He might not have been in the right place to head his dramatic winning goal if City had not gone defensive after being reduced to 10 men by Pablo Zabaleta's 84th-minute red card.
Watson said: "Honestly, it was just a big blur.
"I probably wouldn't have gone up in most games, and it was only due to the fact they had brought everyone back, so there was no one to mark.
"So I thought; 'Why not have a gamble?'. And the gamble paid off.
"If we hadn't had two crucial Premier League games left we'd have had a great party.
"If we stay up, as we believe we can, when we get round to celebrating it will be off the charts."