Connor Wickham felt Sunderland produced two contrasting halves of football as they went down 3-1 at Manchester United.
Robin van Persie and Tom Cleverley found the net inside the first 20 minutes to leave Sunderland with a mountain to climb as they headed down the tunnel at the break.
But despite conceding a third goal in the early stages of the second period, Sunderland upped their game and notched a consolation through former United man Fraizer Campbell.
Wickham's introduction as a half-time substitute ushered in an improved second-half performance after Martin O'Neill delivered a concise half-time assessment in the dressing room.
"The boys knew we didn't perform well in the first half and we had to pick ourselves up," said Wickham, who replaced Steven Fletcher after Sunderland's leading goalscorer picked up an injury in the first half.
"The manager made his thoughts clear at half-time and we knew what we needed to do.
"For me coming on the start of the second half, I knew I had to do all I could to at least try and get us back in the game.
"I thought I did quite well and it was a better performance in the second half."
Sunderland had chances to add to Campbell's goal and mount an unlikely comeback, with Wickham himself coming close on a couple of occasions.
The 19-year-old striker was a handful throughout the second period and says the visitors created enough opportunities to have got something from the game despite finding themselves 3-0 down.
"I always aim to get in the box and create chances, and I think we do create quite a few chances in games as a team," he said.
"It's just about getting enough people in the box to try and finish them off.
"We know we could have reduced the deficit further - we had chances and could have buried them.
"The boys know the first half was not up to scratch, but the second was obviously an improvement."