Championship basement outfit Doncaster dominated the opening period but again failed to translate their possession into goals and Collins punished them by nodding in a precious winner for Mick McCarthy's men.
Victory lifted Wolves seven points clear at the top of the table and unlikely hero Collins was the toast of the 3,216 travelling supporters.
The defender was only named in the starting line-up because on-loan Chelsea youngster Michael Mancienne pulled out shortly before kick-off due to injury.
Collins took his chance in style to heap more misery on Doncaster boss Sean O'Driscoll, who watched his struggling side largely dominate proceedings in an opening half which saw both sides struck the woodwork.
Wolverhampton-born O'Driscoll, 51, grew up in the Black County town as a fanatical Wolves fan but his affection for the club was well and truly shelved as Rovers put the visitors under the cosh from the first whistle..
The Yorkshiremen, desperate for victory to boost their fight with relegation, began brightly and Lewis Guy produced a delightful piece of skill which cut Wolves apart in the ninth minute.
The striker's deft flick outfoxed Matt Hill and allowed him to leave the Wanderers left-back for dead as he tore down the right flank.
Guy's subsequent cross was cleared for a corner but Doncaster continued to worry Wolves with their pace up front.
In the 15th minute, Guy again engineered the space to find the onrushing Paul Heffernan with a neat short pass from inside the visitors' 18-yard box.
Heffernan's first touch was decent and his second with a low right-foot shot straight into Wolves goalkeeper Wayne Hennessey's midriff.
In the 26th minute, the breakthrough almost arrived when Richie Wellens' astute pass sent Heffernan racing clear and he held off Richard Stearman and cracked a rising shot against the top of the crossbar.
However, Wolves went close themselves in the 39th minute when Keogh rifled successive close-range shots against the bar and post before Neil Sullivan produced a smart parried save to further deny the visitors.
Wolves improved after the break as McCarthy introduced Chris Iwelumo and Matthew Jarvis for Keogh and Hill respectively, but the visitors still created next to nothing.
Wellens shot wide in the 47th minute and Collins was booked for cynically hacking down Guy as he threatened to burst clear again.
Wolves did not seriously threatened until the 72nd minute when Kevin Foley cut in from the right flank and hit a low shot straight at Sullivan.
But, as the game looked to be petering out to a dismal stalemate, Collins rose highest to greet Michael Kightly's deep free-kick from the left and plant a firm header past Sullivan.
Any reproduction, publication or redistribution of this material without the written agreement of 365 Media Group is strictly forbidden.