PSV have 40 points from 18 games and lead on goal difference from Twente Enschede who won 3-0 at AZ Alkmaar on Friday.
PSV, who had lost their four previous matches in Breda, showed their determination from the kick off and Lens opened the scoring after 11 minutes when he netted a rebound.
Breda keeper Jelle ten Rouwelaar saved a penalty from Lens six minutes later but the PSV forward doubled their lead before Jordy Buijs pulled one back with a long drive.
Georginio Wijnaldum and Mathias Jorgensen scored before the interval and second-half goals from Luciano Narsingh and Jurgen Locadia took PSV's league goal tally to 60 this season.
"Creating chances never was our problem but today we also finished them with a team that showed great effort," said PSV captain Mark van Bommel.
"We're satisfied that we're on top midway through the season, considering we made a false start this season and also had a tricky phase a few weeks ago with defeats against Ajax [Amsterdam] and Vitesse [Arnhem]."
Fourth-placed Vitesse, on 35 points, fell further off the pace with a 2-1 defeat at Marco van Basten's Heerenveen.
Heerenveen's outstanding playmaker Filip Djuricic put the hosts ahead after 30 minutes but Guram Kashia equalised before the break.
Alfred Finnbogason to seal the win for Heerenveen early in the second half thanks to a blunder by keeper Piet Velthuizen, who misjudged a long drive fired straight at him.
ADO Den Haag's Jens Toornstra struck twice to earn a 2-0 home win over 10-man NEC Nijmegen who had Kevin Conboy sent off with a straight red card midway through the first half.
Den Haag are now eighth and trail Nijmegen by a point.
