Although the Chairboys' play-off ambitions were all but over, it failed to halt their ambition was to finish the last home game of the season with a flourish.
The visitors had themselves searched for an early breakthrough, but Wycombe were ahead inside two minutes thanks to midfielder Matt Bloomfield, who scored his third of the season.
With the O's defence in disarray, home striker Jonny Dixon found acres of space to deliver a stunning throughball that the former Ipswich player drilled past keeper Lee Harrison.
Fine efforts by Joe Burnell and Roger Johnson peppered the visitors' goal as Wycombe continued to dominate. It came as little surprise that on 23 minutes the home side went further ahead.
From a deep Danny Senda corner, defender Johnson rose high at the back to thump a header back across the Orient goal, Mike Williamson was on hand to bundle the ball over the line.
Massive Wycombe pressure finally broke down Orient for their third with the impressive Boomfield again in the thick of the action.
The midfield raced to scramble the ball away from defender John Mackie, sweeping the ball to the feet of Gus Uhlenbeek, who drove past Harrison from ten yards.
With Wycombe content with their first-half work, Orient were denied a goal seconds from the break, home keeper Frank Talia forcing Lee Steele's close-range effort away with his legs.
Orient boss Martin Ling made two subs at the break, Brain Saah and Aidan Palmer coming on for Matt Lockwood and Derek Duncan respectively.
It was Saah who, four minutes after the restart, set up Alexander for his first and just seconds later, Alexander struck again to reduce the arrears further.
Orient were now totally dominant – Donny Barnard missed a sitter and Alexander was only denied his hat-trick by the legs of the flailing home keeper, Talia.
Although rocking from the onslaught, Wycombe's Nathan Tyson managed to hit the post, but was stretchered off after a nasty collision with O's keeper Harrison.
Despite the pressure from the visitors, Wanderers managed to hold on to their slender lead and the crowd were delighted to hear the final whistle confirming three points from the last home game of the season.