Peterborough United suffered late penalty heartbreak as Port Vale converted a 94th minute penalty kick to earn a point from a pulsating 2-2 draw at the ABAX Stadium.
George Moncur had bagged a brace on his first start for Posh following his loan move from Barnsley but McCann's men were undone in the final minute following a performance that deserved all three points.
The visitors opened the scoring on six minutes as Alex JONES rifled home with his left-foot from 12-yards after a cross to the back post was headed back across goal.
It didn't take Posh long to level, less than two minutes in fact as Maddison picked out MONCUR on the edge of the box, he forced his way into the penalty area and drilled a low shot across Alnwick and into the bottom corner.
Forrester was a whisker away from giving Posh the lead after he advanced from the central area of the pitch and let fly, his effort taking a deflection and ending up just wide of the target.
Anthony Grant was cautioned for a hefty challenge on Maddison on 12 minutes, the first caution administered by referee Mr Horwood.
Vale had the ball in the back of the net on the half hour mark as Jones bundled the ball home at the back post, but an obvious foul was spotted by the referee.
Bostwick saw a low free-kick well held by Alnwick on 39 minutes after Moncur was upended on the edge of the box.
Three minutes later and Posh were forced into their first change as Anderson was replaced by Da Silva Lopes after picking up an injury.
Alnwick was called upon again on 43 minutes to deny Maddison's low drive after an excellent pass was fizzed into his feet by Forrester. Paterson was cautioned in stoppage time for a foul on McGee who had claimed a looping Jones header.
Alnwick produced arguably his best save on 50 minutes as he denied Hughes from close-range after good work from Moncur down the left. McGee was well placed to deny a Paterson's low shot as Vale upped the tempo.
Da Silva Lopes was cautioned on 56 minutes for a foul. Grant McCann made a double change just after the hour with Hayden White and Paul Taylor introduced.
Nichols headed over the top from a glorious Edwards cross after some excellent approach play involving Hughes and Moncur.
Posh squandered a glorious chance to get themselves in front on 71 minutes as Taylor danced to the by-line and cut the ball back invitingly for Nichols,but somehow he fired wide of the near post. Bostwick was then cautioned for a foul in the centre circle.
Edwards saw a shot blocked after a low centre from Moncur as once again Posh carved open the Vale defence without that final part of the move to be completed.
Posh got themselves in front on 81 minutes as excellent work from substitute Paul Taylor down the left created a chance for the onrushing MONCUR who made no mistake, calmly rolling the ball past Alnwick and into the left hand corner of the net.
McGee made a fine stop to deny Thomas on 86 minutes after a through ball was deflected into his path. Port Vale levelled deep into stoppage time as Hughes was shown a red card for deliberate handball in the box and JONES tucked home the penalty to make it 2-2.
Posh: McGee, Smith (sub White 62min), Hughes, Bostwick, Baldwin, Edwards, Forrester, Maddison (sub Taylor 62min), Anderson (sub Da Silva Lopes 41min), Nichols, Moncur. Unused subs: Tyler, Tafazolli, Oduwa, Moore.
Port Vale: Alnwick, Purkiss, Streete, Knops, Tavares, Foley (sub Poreira 80min), Paterson (sub Ciclilia 62min), Thomas, Smith, Jones, Grant. Unused subs: Santos, Macintoch, Kiko, Amoros, Hart.
Half-time: Peterborough United 1-1 Port Vale
Full-time: Peterborough United 2-2 Port Vale
Attendance: 4,711 (280 Port Vale fans)