The Eagles looked doomed to relegation as the Allardyce effect did not seem to be working for once and a 1-0 reverse to Stoke City on February 11 left the club languishing in the bottom three.
However wins over Middlesbrough, West Ham and Watford have lifted the Londoners out of the drop zone and up to 16th in the standings, with a four-point advantage over 18th-placed Hull City.
There is still a long way to go and work to be done for Palace to maintain their top-flight status, but they are now in a much stronger position than a few weeks ago and Tomkins puts it down to the work done by Big Sam.
"In recent weeks the boss has taken us to one side on the training ground, both as a defensive unit but also as a team group, to work on our shape with a massive emphasis being on clean sheets, something which he has always been known for, wherever he has managed," he told the club's official website.
"It is not just about the back four and the keeper but also those working from the front, sitting in when needed and then breaking out in numbers on counter attacks when the opportunity comes about in games.
"In recent weeks this work has been paying off because to get three consecutive clean sheets in the Premier League just gives us such a great lift and shows how our defensive play is key to our chances."