Mauricio Pochettino has revealed his key tactical change as he hailed Chelsea's belief-building 2-0 win over Sheffield United.
Cole Palmer and Nicolas Jackson scored crucial goals after important half-time changes by the Blues manager.
Chelsea had barely created any chances against the bottom of the table side but have risen into 10th place, with victory earned through second half improvements.
Pochettino revealed his subtle changes at the interval that helped his side turn the tide following back to back away defeats.
"We made a mistake because we were standing still too much in our positions," Pochettino said at Stamford Bridge.
"We did not show the capacity to be flexible. It was easy for them to identify our positions and to block us and to make us put the ball in the positions that were them easy to stop.
"In the second half, we were much better. We fixed things. Then the team started to find better possibilities to play and link much better.
"Cole from the right, with all the space and the possibility to face the goal, started to link better with team-mates and started to be the player we want to use, as a playmaker.
"We swapped and then the position of our midfielders and full-backs. In the second half I think we fixed different positions and started to find different possibilities with the ball and stretch the line with Raheem and Jackson going into the space.
"We were aggressive enough. But we suffered a lack of aggression in the first half as we made a mistake in the way we tried to penetrate.
"But in the second half I think with the things we changed the team found better solutions."
Chelsea next have an important Carabao Cup quarter-final match at home to Newcastle on Tuesday night.
Pochettino is hoping a third home win in a row can help change the conversation around his west Londoners.
"I am happy because the players deserved the victory," he added. "They worked really well during the week. They react. It is to be more confident but at the same time we need to be alive.
"We need to change if we want to improve. I am happy because three points for us are really important and then on Tuesday we have a very important game against Newcastle that with this victory is completely different with this feeling.
"It is really important with our confidence that we can go through and stay in the Carabao Cup."
