"I just feel in this competition that it should go straight to penalties at this time of year," said Russell Slade after his side lost in Extra time to MK Dons..
"We're playing Saturday-Tuesday, Saturday-Tuesday - it's wrong.
"It's wrong to be doing 120 minutes. I'm sure that there's a lot of managers that would agree with me on that."
Dons boss Karl Robinson said something similar after their 2-1 first-round win over Slade's former club Leyton Orient.
The Cardiff boss also claimed Robinson would have welcomed a penalty shootout at the end of normal time at Stadium MK on Tuesday.
"Both of us would have been happy after the 90 minutes to have gone straight to penalties - I think that's the point," Slade added.
Cardiff travel to Nottingham Forest in the Championship on Saturday and Slade says their opponents will be "delighted" his players had "a tough 120 minutes" in the League Cup.
Alex Revell scored a memorable opener against Dons, earning Slade's praise.
"It was a great volley into the net. It was a well-worked move, a good cross and a good finish and there were some really good passages of play… when we got in front we really should have put the game beyond them," said Slade.
"But there you go. We didn't and we've suffered a defeat."
