It was a 20th minute goal from Andy Morrell which allowed Blackpool to relax at home for the first time this season.
But Orient were far from pushovers in a game full of passion if, at times, lacking in skill.
Jabo Ibehre had a wonderful chance to score in the second minute but his header came back off a post and Blackpool keeper Rhys Evans clawed it away.
Blackpool took the let off in their stride with Morrell twice going near before his first goal for the Seasiders.
The hard working Ben Burgess created the opportunity and Morrell's looping header beat stranded Orient keeper Glyn Garner.
With both sides losing key defenders with injury, the game began to lose its shape either side of half-time.
Orient produced an aerial bombardment of the home goal and at set pieces there were often 15 players in the Blackpool six-yard box.
However, at the other end in the 82nd minute a long clearance from Shaun Barker sprang the Orient offside trap.
Blackpool substitute striker Keigan Parker won the chase into the box and was about to shoot when Adam Tann brought him down.
Wes Hoolahan stepped up confidently converted the penalty and Tann received a red card for his troubles.
Blackpool continued to look dangerous on the break and five minutes later scored the killer third.
Once again the provider was Burgess, who slipped a neat pass through the defence and Parker was on hand to score with a clinical 18-yard finish.
After the game Grayson spoke of his relief. He said: "There is no secret. We have been under a lot of pressure.
"During the week we lost 2-0 but we played some very good football. In this game I didn't think we played half as well but we won 3-0. That's football I suppose.
"However, this is a result which is important to me, the group of players and this club. We needed it very badly.
"What I want now is to match up victories with performances on the field."
Orient boss Martin Ling said: "I did not think it was a 3-0 defeat. We were certainly not that bad.
"We played well for 20 minutes but after we lost our captain we lost some of our shape.
"But I have a great belief in the squad and believe we can start going places if we can sign a couple more players and I know the chairman will back me on that."