Substitute striker Rory Patterson marked his home league debut with his first Football League goal to earn Plymouth a late 1-1 draw against Carlisle.
Patterson swooped to sweep the ball home from eight yards four minutes into injury time to cancel out Ian Harte's 68th-minute header.
Harte, who topped United's scoring chart with 18 goals last term, could have put the visitors in front in the first half.
Argyle's on-loan Tottenham keeper David Button made a top drawer save to deny set-piece specialist Harte from 25 yards in the 28th minute. Harte's thunderbolt looked destined for the top corner until Button sprung to his right to spectacularly palm the ball away to safety.
Both managers persevered with their opening day starting line-ups but before half-time Argyle boss Peter Reid introduced striker Patterson for target man Rory Fallon to pep up his shot-shy attack.
In the 83rd minute Patterson forced a save from United keeper Adam Collin with an angled 12 yard shot but he was not to be denied and struck late on.