The Staggies went down 3-0 at Easter Road, conceding between 22 and 33 minutes, but Mackay was heartened by his team’s performance in the second period.
“All the goals came between the 22nd to the 33rd minute,” said Mackay.
“I thought we started really well, considering we were coming to a terrific team that finished third last year, with a good manager and squad of players.
“In the first 15 to 20 minutes we threatened them in behind McGinn, Jordan White had a good header and Ross Callachan had a good volley.
“We knew the threat they were going to be. We were unfortunate to lose the first goal, I’ve seen it back and it’s a huge deflection.
“We then lost two quick goals. It was something that happened quite a lot last year, that can then turn into a really high scoreline.
“That was something we didn’t want to happen.
“We got in at half-time and I made a couple of changes, I brought on a couple of debutants, and I asked them to be really brave and get on the front foot.
“I thought we did that, playing against a good team I think we caused issues for them as well.
“There was another game today which was 3-0 at half-time and finished 6-0 – so I wanted to make sure that didn’t happen to us.
“I’ve got no complaints. It was a good team to play against, and good learning for us.”