One is his indefatigability, the way his head never goes down after he misses easy chances. The other is his ability to make a telling impact when you have almost forgotten he is still on the park.
Both were evident yesterday as St Mirren discovered to their cost. The Kilmarnock forward barely figured in the first half and, when he finally offered an attacking threat midway through the second, it was to miss two gilt-edged chances. He capitalised on a defensive error to set up his first opportunity, tip-toeing through a few challenges before blazing his shot over the crossbar from around 10 yards. Barely 60 seconds later and he was preparing to shoot when Darren McGregor appeared to make a timely block.
Boyd had contributed little else as play entered injury time but anyone wondering why Allan Johnston, the Kilmarnock manager, had not taken him off was about to find out. Substitute Robbie Muirhead made another defence-splitting pass and Boyd did not have to be asked twice, ignoring the possibility of offside to run on to the ball before slotting a shot beyond Marian Kello.
Other players may contribute more throughout the 90 minutes, but there are few in Boyd's class when it comes to winning matches. It was his 12th goal of the season, his sixth in his last six matches, and had the added effect of lifting Kilmarnock above their vanquished opponents and into eighth place in the SPFL Premiership table.
"I have scored the amount of goals I have in my career because I always go back for more," said Boyd with typical candour. "It was bad finishing on my part for the first couple but I probably scored the hardest one out of the three of them."
"If we get chances to Boydy, he will always score," added Johnston. "He got one and was unlucky with a couple of others. That's how much of a threat he was."
So successful has Boyd been this season then there will surely be one or two clubs wondering this month whether he could do the same for them. "Have I got another level in me to get back to?" added Boyd. "It is up to someone to come and ask me that question. I am not going to try and sell myself."
Johnston was not in a rush to get rid of his star striker either. "Boydy knows how much of a big player he is for us," he added.
This was a third consecutive away defeat for St Mirren and a sore one to take given they contributed plenty to an exciting encounter. If there was any consolation for manager Danny Lennon it came in the performance of Adam Campbell, who followed in the footsteps of Paul Dummett and Conor Newton by becoming the third young Newcastle United prospect to swap one set of black and white stripes for another after signing on loan until the end of the season.
On first impressions, Campbell looks like being another useful addition. Quick, two-footed, technically-accomplished and feisty for such a diminutive figure, he did not take long to make an impact, scoring after just 18 minutes. Steven Thompson's cross arrived at his feet via a flick from Marc McAusland and he created space to plant a low shot beyond Craig Samson. Campbell could have had a second late in the game only for a timely tackle from Jeroen Tesselaar to deny him.
"I thought wee Adam Campbell gave a great flavour of what he's going to bring," said Lennon. "He's got lovely soft feet, a lovely touch and good pace. It will take him a bit of time to settle but that performance - and the goal that he scored - will give him added confidence."
Kilmarnock have talented young players of their own and two combined to draw their team level after 28 minutes. Chris Johnston drifted off his left wing to find Rory McKenzie with a well-weighted pass that was dispatched firmly with a good old thump past Kello. Craig Slater had earlier thudded a shot against the bar.
St Mirren had the best of the rest of the first-half chances but Samson was a goalkeeper in excellent form. Thompson was the first to be frustrated, before Paul McGowan's half-volley was also kept out. Not for the first time the glory fell to Boyd.