Stoke boss Mark Hughes was frustrated after seeing his side rally back from two goals only to lose 3-2 to Southampton in the Capital One Cup on Wednesday.
The Potters made amends for a lacklustre first-half display in which they fell 2-0 down by fighting back and levelling through Mame Biram Diouf with eight minutes remaining.
Stoke appeared to be the more likely winners at that stage but Peter Crouch saw red for two yellow cards in less than a minute. The second was for a foul on Steven Davis and, from the resulting free-kick, an error by Erik Pieters allowed Pelle to grab his second in the 88th minute.
"We put in a huge effort in the second half," Hughes said. "We needed to because in the first half we didn't really get anywhere near the intensity that I was hoping for in terms of making it a real cup tie.
"The difference with the second half was marked. It was a real effort and I thought the momentum was with us.
"At 2-2 I felt we were in the ascendancy and we could go on and possibly win it from a situation where at 2-0 down you think it's going to be very hard against a very good Southampton team."
Koeman argued Charlie Adam could have been sent off at 2-1 for a challenge on Morgan Schneiderlin that earned him a booking -- one of seven shown by referee Lee Mason.
Hughes felt Crouch was a little unfortunate to see two of those -- with the first coming for a clash with Jose Fonte and the second the late challenge on Davis.
"I felt the first yellow card was a little bit harsh on Peter," said Hughes. "I think he made a genuine attempt to just try to get across the lad. Whether or not the referee thought he raised his arm, I don't know.
"The second one, he's miscontrolled it and in trying to retrieve the ball he's high. When you're on a yellow card, there's always a risk you're going to get another one if you go in with a challenge like that.
"We've lost him, and that took a bit of the wind out of our sails, and then we haven't dealt with a ball into our box."