Neil Critchley’s side eased into a comfortable mid-table position thanks to a third victory in four Championship games.
Barnsley, meanwhile, dropped closer to the drop zone thanks to a seventh match without success. Last season’s play-off semi-finalists have still won just once so far this season.
Another mouth-watering Roses battle at Bloomfield Road got off to a rather pedestrian start.
The hosts soon clicked into gear, though, with Lavery forcing Brad Collins into a smart save as he darted in to meet Keshi Anderson’s low cross and Luke Garbutt fired the follow-up opportunity way over the top from 25 yards.
The Tykes were being roared on by a terrific army of travelling support, and they were all off their seats in the 12th minute when Dominik Frieser’s side-footed effort from 12 yards was blocked close to the line.
As the sun began beating down, the Seasiders were next to threaten when Garbutt crashed in another shot from distance which flicked off defender Jasper Moon and fizzed behind.
Barnsley were next to go close when skipper Cauley Woodrow hit an instinctive shot on the turn narrowly wide before Blackpool went mighty close in the 25th minute. Garbutt again sneaked in down the left to meet Anderson’s through-ball, only for Collins to bravely race out and smother the Blackpool man’s close-range effort.
Anderson did eventually create a breakthrough in the 32nd minute, though, when his perfectly-weighted pass was met by Lavery and he tucked home clinically past Collins from a narrow angle.
Barnsley came agonisingly close to a leveller 10 minutes later when Victor Adeboyejo’s crisp effort was expertly palmed away by Chris Maxwell.
The visitors began the second period on the front foot and Callum Styles lashed in a 25-yard strike that only just cleared the crossbar.
The lively Anderson replied in kind for Blackpool, drilling a low effort just past Collins’ far post, while the goalkeeper was also tested by goalscorer Lavery from 15 yards.
It was the hosts who continued to press the most as the game wore on beyond the hour mark and Tyreece John-Jules was unfortunate when his well-struck left-foot drive was deflected behind.
It was looking like Barnsley were beginning to run out of gas but Woodrow almost notched in the 85th minute when his tight-angled shot from close in was saved by Maxwell.
Michal Helik headed off target late on for the Tykes as Blackpool secured the points.