Aberdeen manager Barry Robson took responsibility after his side put in a laboured performance in a 2-0 defeat to Kilmarnock at Rugby Park.
The Dons failed to create anything of note as goals from Kyle Vassell and Marley Watkins either side of half-time gave Kilmarnock a deserved win.
Robson admitted he should have made more than the one alteration from the side who threw away a two-goal lead to lose 3-2 to PAOK on Thursday night in the Europa League.
He said: “We were poor today. In the first half, I didn’t think it was a very good game. They scored right before half-time, which was a bit of a sucker punch for us.
“But the biggest problem was probably my fault. I should have freshened the team up more from Thursday night.
“It was pretty evident that we looked leggy in the first half. We made a change at half-time and tried to change the shape, but it’s hard.
“That was on me. We needed some fresh legs. I think we would have seen a different team today.
“We’re not looking for excuses. We should come down here and try to win the game. We weren’t at our best at all. I should’ve changed it from the start and I think we’d have had a better outcome.”
Aberdeen remained in 10th position in the cinch Premiership and the Dons manager also admitted results have not been at the required level.
He added: “Our league form hasn’t been good enough. It’s been stop-start, with games being cancelled or moved.
“But if you want to play at this level, play in Europe and go far in cups, you need to deal with that.
“We’ve not dealt with it so far, so we need to start doing that better.
“We’ve got a massive game against Motherwell in midweek and if we can go and win at Motherwell, that can race us up the league and then there’s the chance to reach a final against Hibs next weekend.”
Kilmarnock manager Derek McInnes was delighted with his side’s first clean sheet in nine games as they secured back to back wins in the league for the first time this season.
The home side moved up to fourth place in the league with the impressive victory.
McInnes said: “Everything is better than last season but we spoke at the team meeting about getting more clean sheets. Last week was a clean sheet display but we gave away a penalty.
“We had to deal with two key players missing in Corrie (Ndaba) and Joe (Wright) at the start of the second half. We’ve still got the clean sheet and my keeper hasn’t been too troubled.
“It was a good performance with strong individual performances. I don’t normally like singling boys out but Lewis Mayo was so good, especially with a three v three defensively which was a big test for us.
“It’s nice to follow up a strong display with another and to see us sitting where we are in the league.
“You don’t look at that too much until the first couple of rounds but I want to hang about there for as long as possible.”