The on-loan striker once again stood out for his third and final game for the Lions, but despite seeing Clive Clarke's early strike cancelled out the visitors held on for a deserved point.
In an amazing start to the contest Potters forward Carl Asaba threatened an immediate breakthrough, but his swirling lob bounced agonisingly off the foot of the post.
That however proved merely a pretext to the third minute opener when captain Clarke found the net with a beautifully struck 25-yard effort.
Undeterred, the Lions gradually fought their way back into the tie and duly scored a leveller after 23 minutes.
Peter Sweeney, a constant threat down the left, provided a pinpoint cross to the penalty spot where Dichio coolly headed past Ed de Goey.
The home side pressed forward thereafter with Neil Harris and Dichio having chances to grab the lead, but both fired narrowly wide.
Both sides then spurned glorious chances in first-half injury-time. Andy Marshall saved well from Asaba, before the marauding Kevin Muscat fluffed his close-range finish over the bar.
The defences tightened up after the break and despite open periods of play, chances were at a premium.
In the 68th minute, City's Dutch winger Peter Hoekstra forced a full stretch diving save from Marshall with a 30-yard curling free-kick.
Five minutes later the Lions seemed to have found the net, but Dichio's header was acrobatically cleared off the line by John Halls.
Seemingly determined to end his spell at The Den on a high, Dichio almost secured the points late on, but from Dennis Wise's near post corner De Goey kept out his well-struck volley.