The Gunners won 4-0, with Ipswich fullback Leif Davis sent off for a nasty challenge on Bukayo Saka in the first-half.
"A really tough game, two different games to a certain extent,” McKenna said. “Tough at 11-v-11. Arsenal started really well, I probably felt at the start of the game maybe the highest standard that we’ve faced this year, to be honest.
“The group was absolutely at full stretch trying to compete in the first 20 or 30 minutes. We had a few moments where we could have hurt the opposition but in the end their execution was better than ours and their quality shone through in the goals and they were the better team and deserved their lead at that point.
“Of course, then the red card makes it almost an impossible task in terms of getting back into the game and I thought the group showed good qualities with 10 men, to be honest.
“The second half’s a really tough situation, I thought we managed it well. Defensive organisation, spirit, resilience was really good, didn’t give up too many things in free play."
Set-pieces made difference for Arsenal
McKenna also admitted: “We knew if we did that we’d get one or two moments around their box. We had a similar situation in the Aston Villa game earlier in the season (when also down to 10 men) and we actually had a couple of little moments. You need it to go in the net really to have a chance in the game, but it didn’t.
“Just disappointed with a couple of short corners, which were difficult to deal with.
"They’re good on short corners and when you lose a man that’s a moment where it becomes really difficult because without giving up too much in the box, it’s hard to match up the numbers they have in the short (areas) even with 11-v-11.
“Disappointed that a couple of short corners ended up going in the net but I thought in the second half the group showed the right qualities that they needed to show in that instance.”
"I can see why Davis sent off"
On Davis' red card, McKenna admits he had no complaints over the decision: “At the time I didn’t think it was but it was on the far side of the pitch and that’s more in line with knowing Leif as a player and I don’t think he’s got a malicious bone, really, so I don’t think there will have been the intent to injure.
“But when you see it on the video, it’s obviously a high challenge, and I’m pretty certain with no intent, but it’s a high challenge, so I can see why the referee gave it and when it’s given, it’s never going to be overruled, so we can’t have too many complaints.”