Watford dominated the first half with Matt Gilks saving Troy Deeney's penalty, and Italian Davide Faraoni striking the woodwork twice in a half controlled by the visitors.
But whatever Ince said at the break worked as Blackpool were much improved after the interval with the manager's son sealing the win in the 81st minute with a wonderful solo strike as he waltzed past three defenders before rifling a brilliant finish into the bottom left hand corner.
"If it had been a boxing match it would have been all over at half-time," said the Blackpool boss.
"Watford were outstanding in the first half and if they had scored the penalty it would have been a different game.
"We rode our luck and sometimes you earn your luck. When you have central midfielders, one at right-back and the other at centre-half, you're going to ride your luck.
"Gilks made a fantastic save from a penalty. I couldn't wait to talk to them at half-time. We showed them too much respect.
"Gareth Southgate rang me (on Friday); Tom has been out for three weeks. He asked me if Tom wanted to go down and join up with the (England) Under-21s and train then he could.
"But I told him I'd put him on the bench as a threat, never to play him, just for Watford to take their eye off the ball. I had no intention of playing him."
Watford remain on the cusp of the top six despite the defeat, but after dominating the first half, missing a penalty and striking the woodwork on multiple occasions, boss Gianfranco Zola could not believe his charges had left Lancashire empty-handed.
"I cannot believe we lost the game," said the stunned Italian.
"Actually I can, it happened last season a few times. We had complete domination and then we got sloppy in the second half.
"It was like Millwall away last year, but even more so. This is the Championship, that's why people say it's such a difficult Championship.
"We lost too many individual battles and that gave them energy, fuel, courage. Slowly we lost our securities. Not that they created so much, but we weren't on top the same as the first half.
"We should have had four or five but that's not enough to win a game. We have to take our chances and when we lose the momentum in the second period we have to be more solid.
"It was a superb goal from a superb player, I don't have any complaints. They scored a great goal and I was the first one to clap."