It was an Edinburgh derby that rarely ignited at Tynecastle with the visitors missing out on the chance to go level on points with third and fourth-placed Inverness and Motherwell.
But it was a reckless challenge by Hearts midfielder Stevenson on skipper James McPake that had Fenlon saying: "It's a shocking tackle. He had a look first before he left the ground.
"We're disappointed with that. He has a bad gash, James. There could have been a bit of damage there, but he's not too bad. But you can't be critical of the referee. I thought the referee reffed the game very well."
Hearts boss John McGlynn added: "I haven't seen it again. I think the referee was in a good position. It's a derby game, it's competitive. In derby games four or five years ago that wouldn't have been an issue."
The result was a bit of a comedown for the visitors following their phenomenal 1-0 triumph over leaders Celtic at the weekend.
"It was hard fought," Fenlon told Sky Sports. "We had to defend really well. It was a battling performance rather than a classic.
"The Saturday game seemed to take its toll on some of our lads where they put in quite a shift.
"But coming here was difficult. It's credit was haven't conceded a goal after being put under some pressure."
And with the winter break set to kick in, Fenlon added: "I'm delighted with the first half of the season.
"There's no comparison to last season. We've got some real battling qualities."