Craig Brown said the score was a fair reflection and Preston got the lucky break when they needed it with the own goal. He singled out Michael Jackson, Richard Cresswell and Brian O'Neil.
Gillingham manager Andy Hessenthaler said it was a bad day and it was disappointing and Preston deserved to win.
Marlon Broomes went off with an injured thigh after 22 minutes and was replaced by Tyrone Mears.
Preston made it 1-0 in the 29th minute when a Lee Cartwright right-foot, right-wing cross fell to Eddie Lewis who curled a seven-yard right-foot shot to the keeper's left.
Paul McKenna ran into the penalty box down the right and was tripped by Hessenthaler and the referee awarded a penalty. Graham Alexander hit the 38th minute kick right-footed into the net to make it 2-0. It was his seventh penalty and eighth goal of the season.
The fourth official signalled two minutes extra as Preston went in 2-0 up.
Rod Wallace came on as substitute for Paul Shaw who may have tweaked a cartilage.
Preston made it 3-0 with a lucky own goal from Barry Ashby after 55 minutes after a great run and pressure by Cresswell.
Hessenthaler substituted himself and brought on the fresh legs of Nayron Nosworthy after 62 minutes and then Roland Edge was withdrawn for David Perpetuini four minutes later.
Preston took off George Koumantarakis for Simon Lynch after 74 minutes and Chris Lucketti, the Preston captain, was booked for a foul on Guy Ipoua four minutes later.
Erik Skora was replaced by O'Neil with ten minutes left and Mamady Sidibe was booked for a foul with four minutes left.
The fourth official signalled three minutes extra, but Preston had long sonce sealed their emphatic 3-0 win.