Russell Martin says Cameron Congreve and Olivier Ntcham were both withdrawn during the 2-1 loss to Middlesbrough due to Swansea City's lack of intensity in the final third.
The visitors started well but conceded twice in the first half as Riley McGree and Matt Crooks both netted.
Congreve was withdrawn shortly after the half hour mark at the Riverside Stadium while Ntcham was substituted at half-time as the Swans desperately looked for a route back into the contest. They pulled a goal back through Joel Piroe late on but couldn't find an equaliser after having Ben Cabango sent off three minutes from time.
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Martin said post-match that his side were once again left to rue their own mistakes in the north east of England.
"We started the game really well, loads of purpose and control," he said. "We make a mistake and don't react well enough to it. That's a sign of where we're at at the minute, we're really getting punished for those mistakes.
"It's probably a sign of having a young team. We had a wobble for 10 minutes which leads to the second goal. After that, the boys couldn't give us any more in the second half.
"It felt like it was coming, and it did, we got the goal, but Ben makes a mad decision. It's not the reason we don't go on to get something because we were still so dominant, we looked like we were really dangerous, but that decision and getting sent off is probably a sign of where we're at.
"There wasn't enough willingness to run in the first half, too safe, guys not running to give each other time and space on the ball.
"We played brilliantly until we got to their final third, and that was because of a lack of intensity on the top line. It's why we made a change, not because Cam made a mistake. He's going to be a brilliant player, today will be a huge learning curve for him. But we had to change something at that point.
"The same with Olivier at half-time. The guys who came on had a real willingness to run, stretch the defence and make it a bit messy in the final third.
"Joel Piroe scored, he deserves that. I said to the guys after the game, he scored however many goals he did last year, it would have been so easy for him to come back with a mindset that he might be moving. There's been so much noise around him.
"He's just a brilliant guy, he deserved that goal. We need more like that who just have courage, regardless of the situation they're in."
When asked if he is confident of keeping Piroe beyond Thursday's 11pm transfer deadline, Martin responded: "I hope so. I don't think I've ever said I'm confident of keeping him. I can't be confident of something that's just not in my control.
"I hope we can keep him, I really do. That goal will do him the world of good. He's outstanding to work with, he's a real talisman for us."
Martin remains eager to add to his squad in the final days of the summer transfer window, with Wolves midfielder Luke Cundle among those who could potentially move to south Wales, but concedes any additions will be young and raw.
"The second-half team in particular was so young, so you have to expect some bumps and bruises," said Martin. "We've got some really exciting young players at the club, but I think we need a little bit of help.
"If we end up doing that, it's probably going to be really young because of the finance we have which is not very much. If we end up doing something, it will be something that works for us because of the cost of it.
"For the market we're in, there's not going to be any more experienced players. It will be more young guys, I expect, that will come in and we'll have to try and help develop them very quickly."
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