Steve Davis insists Crewe cannot afford to keep conceding from set pieces after Matthew Pennington's header gave Tranmere a 1-0 win.
On-loan Everton defender Pennington scored the first goal of his professional career in the 28th minute, heading home after finding himself unmarked at a Jason Koumas corner.
That was enough to give Tranmere their first win of 2014 with Crewe unable to build on their midweek victory at home to MK Dons as they remain perilously close to the bottom four.
Crewe are one point clear of 21st-placed Sheffield United, who have two games in hand, and boss Davis wants his players to start making life easy for themselves at corners and free-kicks.
"We have conceded too many goals over the course of this season that are similar to the one that has cost us here," said Davis.
"It boils down to one player switching off at a dangerous time and that was the difference really. We would have taken a point.
"The first half was really scrappy and neither team looked like scoring. After the break we came out and pushed them back.
"We played much better but didn't show any real quality in the final third. We had a few chances and a few efforts on goal.
"But we didn't really have anyone who was able to produce a little bit of individual brilliance or put together a good bit of combination play.
"In the end it has come down to a set play. Tranmere managed to hit the right area with a corner and they managed to get a good header in."