Second half goals from Sam Mantom and Andy Taylor secured the crucial win which sees the Saddlers move back up to second in League One.
Following a first half dominated by the hosts, Walsall were fortunate to get to the break all-square.
But they turned the clash on its head in the second half, with the goals from Mantom and Taylor just reward for a more attacking, positive display.
A goal from substitute Liam Mandeville gave Doncaster late hope, But O'Driscoll's side held on in a nervy last 10 minutes to clinch the points.
The match marked O'Driscoll's first competitive return to the Keepmoat Stadium where he enjoyed huge success as Doncaster manager between 2006 and 2011.
As well as securing the Johnstone's Paint Trophy, the boss also guided the South Yorkshire outfit into the Championship before stabilising them in the division.
And the 58-year-old sprung a surprise in naming his starting XI, with Milan Lalkovic returning to the side at the expense of Rico Henry.
It meant the Saddlers continued to operate in a 4-2-3-1 formation but with Lalkovic on the left, Anthony Forde on the right and Romaine Sawyers behind Tom Bradshaw.
Craig MacGillivray started in goal for the injured Neil Etheridge.
For Doncaster, ex-Saddler Andy Butler missed out through injury while deadline day signing Chris Neal started in goal.
Fresh from a weekend without game, Donny were quickest out the blocks and had the home fans appealing for a penalty inside the opening minutes when top scorer Andy Williams knocked the ball against the arm of Paul Downing.
But despite strong protests from the striker, referee Barry Toner correctly waved play on with the Saddlers defender having no time to get his body out of the way.
The penalty appeal aside, chances were proving few and far between with a well saved distance strike from Sam Mantom the closest the Saddlers came to breaking the deadlock inside 20 minutes.
It was Doncaster though who had the more attacking intent and they came close to taking the lead just moments later.
Williams' saw a dangerous cross pushed out by MacGillivray but the ball fell kindly for the onrushing Paul Keegan who took aim but saw his shot expertly blocked by Adam Chambers.
With the home crowd now behind them, Darren Ferguson's side continued to press and had two quick-fire chances in the space of a few minutes.
First, a James Coppinger corner was flicked on to the well-placed Aaron Taylor-Sinclar who hit a smart volley against the top of the bar.
Williams then galloped into the box and brushed off the challenge of Paul Downing before curling a strike towards the bottom corner which drifted just inches wide.
Walsall responded on the half hour mark with Lalkovic's free-kick from the edge of the box comfortably saved by Neal.
It was Doncaster though who were dominating possession and creating chances with the Saddlers happy to trundle off at the break with the scores level having produced very little in the final third.
With their half-time instructions, the Saddlers came out a different start after the interval and almost took the lead after forcing an early corner.
Downing looked to get on the end of a Lalkovic delivery with a combination of the Saddlers defender and Taylor-Sinclair turning the ball onto the crossbar before it went over.
Suddenly O'Driscoll's side were getting balls into the box with Lalkovic heading a Forde cross straight at Neal.
And Walsall's renewed positivity was rewarded on the hour mark when they took the lead through Mantom's fifth goal of the season.
The 23-year-old did excellently to brush off a number of challenges and get to the edge of the box before unleashing an unstoppable strike into the net which had all the hallmarks of midfielder's winner at Brentford.
Five minutes later and the score was 2-0. A corner routine straight from the training ground bamboozled the Doncaster defence with Sawyers then sending in a low cross.
The ball was half cleared as far as Taylor who kept his composure to fire home from eight yards.
O'Driscoll made his first chance in the 75th minute with Henry coming on for Lalkovic.
But Doncaster brought themselves back into the game with 10 minutes remaining when sub Liam Mandeville curled a wonderful strike into the bottom corner and beyond the diving MacGillivray from 20-yards.
With the wind in their sails, Mandewille almost pulled his just level just moments later when his low shot from inside the box was well saved by Walsall's number two keeper.
Fellow sub Mitchell Lund then headed wide from a deep free-kick.
The Saddlers were having to survive a late onslaught but they dug deep despite four minutes of stoppage time to ensure they returned to winning ways in League One.

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