Dundee United manager Peter Houston rued defensive mistakes following the 5-1 defeat by Celtic.
Johnny Russell's strike was the only reward for an entertaining display as United lacked Celtic's ruthlessness in front of goal.
"Zaluska has won man of the match and that tells you something. We've come here and had a go but there's a lot to work on defensively," said Houston.
"But all credit to Celtic for taking their goals."
Russell had cancelled out an early Anthony Stokes header but goals from Gary Hooper, Ki Sung-Yeung, Joe Ledley and James Forrest gave Celtic a commanding lead and three points.
"If you look at the goals we gave away: two (have come) from corners," said Houston. "The first goal, our goalkeeper should do better and they eventually get a corner because he's not concentrating enough," he said.
"So, that was a cheap goal to give away.
"We got back into it with a decent goal and then we go 2-1 down from another corner which is normally a strength of ours.
"For a spell in the second half I thought it was going to go to 2-2 because of the number of crosses we were putting into the box.
"But they counter-attacked us again to make it 3-1. So, it's disappointing and really poor defensively for us. We looked a threat at times in an attacking sense, but I'm disappointed to lose to a scoreline that flattered them."
Houston said it was better to judge his side against the non Old Firm teams, because of the difficulty in facing Celtic and Rangers.
"If we had gone 2-2 then I think their fans would've got edgy," Houston added.