Leyton Orient missed the chance to put clear water between themselves and fellow promotion-chasers Grimsby in this stalemate at Brisbane Road.
It was Orient's seventh consecutive clean sheet at home, but both sides could have won the game in stoppage time. With 90 minutes on the clock, Orient carved out their best chance of the match, but when on-loan signing Wayne Corden found himself clear at the far post he fired over.
Then deep into stoppage time, Grimsby broke away and the hugely impressive Marc Goodfellow fired in a 20-yard effort that bounced off the Orient bar, and as the home defence failed to clear he flashed another effort inches wide.
With so much at stake, the first half was an untidy affair, full of effort but with little inspiration. Although both sides were forced into a re-shuffle, Grimsby lost defender John McDermott with an injury after 21 minutes, while Orient's Donny Barnard limped off five minutes later.
The only effort on target in the first half came when Corden's run opened up the Grimsby defence, but his shot was pushed away by the alert Steve Mildenhall.
After the break Orient took a stranglehold but failed to find a way past giant defender Robert Jones and company. Corden fired a shot just wide while Orient substitute Jabo Ibehre, on for Paul Connor, cut in from the left but his shot was well saved by Mildenhall.
Orient's hard-working midfield man Michael Simpson then tested the visiting keeper, who saved easily at his near post.
Then came the drama-drenched finale. With time running out, Joe Keith's long raking cross picked out Corden but the winger hesitated before firing over.
Little had been seen of Grimsby as an attacking force, but Goodfellow almost won it with his last-gasp effort that rattled the bar - but the result keeps the O's in third place, one above the Mariners.