The Sky Bet League Two Player of the Month for November headed in his 16th of the season after 12 minutes to put the O's ahead at One Call Stadium, but Mansfield claimed an equaliser five minutes before the break through Reggie Lambe's volley.
Following heavy rainfall throughout the morning referee Darren England called a pitch inspection for 1:30pm where he then deemed the pitch playable.
With the game on Orient Head Coach Ian Hendon made four changes to the side that started the previous week against Scunthorpe.
Alex Cisak, Cole Kpekawa, John Marquis and top scorer Jay Simpson all returned to the side as the O’s lined up in a flat 4-4-2 with Blair Turgott and Jobi McAnuff out on the wings.
Despite wet and windy conditions the O’s looked to adjust quickly and having enjoyed a comfortable opening period edged ahead on the 12th minute through no other than the prolific Jay Simpson.
Having turned in the middle John Marquis drilled the ball out to Jobi McAnuff on the left who on his first League start of the season then delivered a brilliant ball into the box for Simpson to crash a header beyond Stags goalkeeper Brian Jensen and register his 16th of the season.
Looking good value for their lead Marquis then worked a chance for himself moments later, collecting a pass from Blair Turgott before drilling a powerful shot over the bar from 20-yards.
As the half wore on Orient looked to be well in control of the tie but with five minutes to go until half time the hosts levelled the tie.
Craig Westcarr’s ball in from the right dropped nicely at the feet of Reggie Lambe who then struck a precise volley towards the bottom corner which then looked to take a slight touch of striker Matt Green to find a way beyond Alex Cisak’s dive.
Given how the half had gone the equaliser was certainly harsh on the O’s, but Jean-Yves M’Voto had the chance to restore their lead when he rose well to get on the end of Lloyd James’ corner but he could only send it over as the sides went into the break even.
During the break neither side made any changes and following an early bit of pressure from Mansfield Simpson came close to adding his second of the afternoon when he swivelled on Cole Kpekawa’s knockdown before rifling a shot inches too high.
With just over an hour played Ollie Palmer was then brought on in place of Turgott to face his former side, but seconds after his introduction the striker nearly saw the hosts take the lead Krystian Pearce crashed a header off the foot of the post from Adam Chapman’s corner.
Palmer then had the opportunity to make an instant impact at the other end a minute later when he received a pass from Simpson in the box and knocked the ball on to his right foot but was unable to get his shot away as two defenders combined to deny him.
The game was swaying in the hosts favour as they upped the pressure and a Stags corner dropped to the feet of Lambe 12-yards out but McAnuff did well to deflect it behind for a corner.
Chances were at a minimum late on as with 87 minutes played Mitchell Rose then tried his luck from distance but his shot was well gathered by Cisak with both Green and Lambe ready to pounce on any rebound.
That was to be the closest either side would come in the closing stages however as both were made to settle for a point each.
MANSFIELD: Jensen, Collins, Tafazolli, Pearce, Adams, Rose, Chapman (C), McGuire, Lambe, Westcarr (Blair 66), Green
SUBS: Shearer, Marsden, Beardsley, N Thomas, Yussuf, J Thomas
GOALS: Lambe (40)
BOOKINGS: Green (42), McGuire (53)
ORIENT: Cisak, Clohessy, Baudry (C), M’Voto, Kpekawa, Turgott (Palmer 64), Payne, James, McAnuff, Marquis (Pritchard 78), Simpson (Kashket 78)
SUBS: Grainger, Essam, Dunne, Shaw
GOALS: Simpson (12)
BOOKINGS: McAnuff (37), Kpekawa (43), M'Voto (90+3)
REFEREE: Darren England
ATTENDANCE: 2,935 (444 Orient fans)