A Ross Bryan penalty and a fine John Carson try from a Bryan kick play eight minutes into each half put the home side 8-0 ahead, but the visitors came back into it as the penalties - and yellow cards - flowed, and fly-half Scott Thomson reduced the deficit with one such penalty before winger Jamie McKay scored in the corner nine minutes into injury time to consign Irvine to their first draw since a 24-24 stalemate at RHC in March 2011.
This result, coupled with victory for Newton Stewart at home to Garnock, leaves Irvine just four points clear of bottom spot. They next face a trip to New Anniesland to take on a Glasgow Accies side no doubt eager to make amends for their September defeat at Marress.
Both sides had a look at each other in the early exchanges before Bryan edged the home side in front with his penalty on 8 minutes.
The visitors patiently worked the ball through the phases for a while afterwards without making much of an impact, but should have scored on 23 minutes when McKay raced for the line, but then unselfishly attempted one last pass to an unsuspecting team-mate when it looked easier for him to score himself.
Irvine were unable to clear their lines from the resulting scrum and had another narrow escape shortly afterwards when the Glens number 8 gathered at the base of another scrum and tried to dart over down the blind side, only to be ruled to have put a foot in touch.
Irvine passed up a good chance of their own shortly after the half-hour when scrum-half Robbie McVey found himself in space deep in the Glens half, but lacking support. Bryan then had a chance to extend the home side's lead with a penalty for offside, but his kick from a relatively central position was wayward.
Irvine stepped things up after the interval and finally notched the game's opening try on 48 minutes.
Ross Bryan spotted some space in behind the Glens defence and sent through a nicely-weighted grubber kick, which found the alert John Carson who needed no second invitation, kicking ahead and outpacing his marker to win the race to the touchdown. Bryan was unable to add the conversion from wide.
This should have been the cue for the home side to kick on and take control of matters, but a spate of yellow cards ensured it remained very much anyone's game. Centre Craig Lang was the first to walk, having been ruled guilty of a spear tackle. Thomson opted to take on the kick but was unable to find the target.
The pendulum looked to have swung back in the home side's favour when a Glens forward was sin-binned for persistent killing of the ball, but he was followed within minutes by Irvine's Robbie McVey, who was ruled to have made illegal use of the boot at a scrum. This time Thomson did kick the goal, and the visitors were back at 8-3 with a quarter of an hour to go.
The visitors won a penalty at the kick-off reception, but this was reversed after the Glens hooker became the fourth player of the afternoon to be sent to the bin for violent conduct. Ross Bryan kicked for goal but was unable to score.
That miss was to prove crucial in injury time as Irvine's discipline deserted them and after several patient phases of possession on the Irvine line McKay finally made amends for his earlier error, darting over in the corner to equalise. Thomson's conversion could have snatched an unlikely win for the visitors, but his kick was comfortably wide and it finished honours even.
Marress played a friendly at Whitecraigs after their league match at Paisley was postponed, which was won 24-5 by the home side. James Cooney notched the only score for the visitors. They are now due to entertain Dalziel 3rds in what is sure to be a lively contest with only seven points separating the sides in the league.
IRVINE -- K Hobson; S Nunan, C Lang, K Lang (capt), M Sneddon; R Bryan,
R McVey; S Docherty, M Kirk, E Callaghan, A Thomson, J Doolan, A Lang,
C Maxwell, R Filander.
Subs: T Wright, D Kirkwood, J Carson, I Speirs.
REFEREE -- Stewart McLean