Wolverhampton Wanderers lost 2-0 to Brentford at Molineux on Wednesday night.
Wolves went into the break 1-0 down against the Bees, and Jackett was keen to see his side improve in the second period.
However, his team-talk had little impact, and Wolves ultimately went on to lose the match 2-0, with Brentford sealing their success late on.
"There were harsh words at half time and we needed to change it because the pattern of the second half started exactly the same," he said.
"We changed the system and a couple of players and had an initial reaction and started to get going with [Rajiv] Van La Parra having one or two runs.
"But then after that the game petered out and we conceded a poor goal on the counter attack to finish it off."
Wolves' defeat to Brentford was their second in a row, and leaves questions being asked of the squad.
Jackett's side almost made it into the play-offs last season, and there were high hopes that they could mount a sustained promotion charge this time around.
However, their form has been middling at best since the start of the new campaign, and they have struggled to meet expectations.
Wolves are currently sat in 12th place in the Championship table, and they already have six points to make up if they are to make it into the play-off spaces.