Craig Levein left Pittodrie feeling short-changed after Aberdeen capitalised on their man advantage to win 3-2.
After Sam Cosgrove's opener, Steven Naismith and Jamie Walker put the Jambos ahead.
However, Aaron Hickey was sent off not long after and the Dons fought back through a Cosgrove penalty and Ryan Hedges' close-range strike.
“I’m left ruing some bad decision making because I thought we did more than enough to take something from the match," the gaffer said.
“He [Aaron] is quite a sensible boy, it was a deserved booking in the first half and I can’t complain at the dismissal because he’s dived in when he didn’t need to. He’s a great kid and he’ll learn from it, he’ll get better.
"We’ve come here a few times and been well beaten but I thought we deserved three points today."
The Jambos made two changes after going behind, bringing on both Naismith and Conor Washington. Instantly, the game changed as Naismith scored with his first touch as a permanent Hearts player.
“Steven Naismith is a good player and bringing him and Washington onto the pitch is something I couldn’t do last year. I didn’t have much choice to leave them on the bench due to their recent injuries but they both affected the match, and the opposition, as Aberdeen were on the back foot when they came on."
There was some bad injury news as John Souttar limped off before half-time with a knock to his left ankle.
“John Souttar has rolled his ankle, it’s started to swell up so it looks like he’s damaged some ligaments but we’ll see what happens in the next few days before we made a decision on scanning it or anything.”