But there was no shortage of drama in the closing stages. Boston fought back from a one-goal interval deficit to claim an 88th minute lead through Paul Ellender.
However, the visitors shared the spoils in the final seconds of stoppage time with Daryl McMahon's second goal of the game.
There was little to choose between the sides early on with Orient going close when Efe Echanomi saw a shot parried away by Nathan Abbey and Boston replying with a fierce free-kick by Danny Thomas which flew wide.
But the visitors went closest on 17 minutes when a ferocious 30-yard shot by David Hunt forced Abbey to tip away at full stretch.
Boston first effort on target took 28 minutes to arrive but then O's keeper Lee Harrison confidently held an Ellender header from a Thomas cross following a short corner move with Kevin James.
But it was Orient who went ahead in the 32nd minute when McMahon forced the ball in from close range after home defender Austin McCann had deflected an Andy Scott cross into his path.
Boston lost the services through injury of striker Daryl Clare just before the break but moments later almost equalised when leading scorer Andy Kirk saw a close-range snap-shot pushed away by Harrison.
Boston finally sprang to life at the start of the second half fuelled by the introduction of substitute Jason Lee.
And it was via his flick-on from a Chris Holland cross on 50 minutes that Mark Greaves fired across goal for Kirk to score.
Orient replied with a forceful break down the right by Echanomi, but from his cross Hunt fired too high.
Boston maintained their heightened tempo and twice in quick succession Kirk just missed out, first been denied by Harrison and then flicking a 69th minute shot wide.
Boston continued to exert most of the pressure and were rewarded in the 88th minute when Ellender rose at the far post to head in from Thomas' curling free-kick after Lee had been fouled by Justin Miller.
But in the final seconds of stoppage time Orient levelled when McMahon turned in a cross from Matt Lockwood.