The ex-Rangers' striker scored three minutes into the second half to put Kilmarnock ahead, but a rush of blood on the hour mark, when he needlessly punched Jim Goodwin earned him a red card, handing St Mirren an extra man and the initiative to collect their first Premiership point.
Goodwin, himself no stranger to red cards, had a degree of sympathy for his opponent but ultimately felt that the referee had little option.
The Saints' captain said: "It was a great battle and a good scrap with Boydy but he maybe thought I intentionally elbowed him when we challenged for the ball. I have possibly caught him but he caught me during the game.
"I've done stupid things in the past, but he reacted badly and made it easier for us when he was sent off."
Rugby park boss Allan Johnston had no argument with Boyd's dismissal but was bitterly disappointed that his rash response cost his side their first win of the season as they went on to draw 1-1.
"I didn't quite see it and it is not like Boyd to do that but he has apologised to the boys for his stupid reaction. He got the goal and he's such a big player for us but his sending off changed things.
"We were in control of the match until that point but then we were left hanging on until the end. But it was a great reaction from the players and they did well to hold on for a point."
Kilmarnock had withstood a storming start from the home side when Craig Samson, on his first return to Paisley since his summer transfer, produced a magnificent save to deny his former team mate Steven Thomson.
It looked only a question of time before the Buddies would be rewarded but before the interval the Ayrshire side had settled and only a terrific diving save from David Cornell denied Paul Heffernan the opening goal.
It was role reversal at the start of the second half. Prompted by the quick footed Rabiu Ibrahim, Killie created a couple of chances before Boyd expertly prodded Sean Clohessy's low cross behind Cornell for his second goal of the season.
But with his side chasing a killer second goal, Boyd saw red and within four minutes his foolish actions were punished.
Samson produced another wonderful save to again deny Thomson but the keeper was helpless as his defence failed to clear Danny Grainger's corner, allowing Heffernan to swivel and ram the ball home from 8 yards.
While the striker celebrated his first goal for the Saints it probably had more effect on the away support after his acrimonious departure from Rugby Park in January.
The home side dominated the remainder of the match and although Samson's goal had a charmed life at times, Saints failed to take advantage of their extra man or one of their many chances to take all three points.
That fact was not lost on Danny Lennon, who took a mixture of satisfaction and disappointment from the game.
"First and foremost we were delighted to take our first point," Lennon said.
"We showed great creativity and played some great football especially in the first 15 minutes and the last half hour. It was a great game and Kilmarnock defended admirably when they went down to ten men.
"However from our point of view it was two points dropped. Steven Thompson was outstanding and he could have a couple of goals but Craig Samson has made some terrific saves, although I'm not sure he knew much about a couple of them."
Turning his attention to the home games ahead and his side's ambition not to finish second bottom this season Lennon concluded: "We want to climb the table. In these circumstances, with an extra man and the number of chances we had, we need to take maximum points from our home games."