The former Rovers boss was installed a few hours after a majority of the club's committee voted to dismiss Wilson less than four months after he took over from Gary Ansell at the end of October.
The Essex club's side was in trouble when Wilson left his post as East Thurrock United's assistant manager for Burroughs Park and they are currently nine points from safety and looking destined for a return to the Essex Senior League after taking just 10 points from a possible 57 under his guidance.
O'Connell's first chance to engineer a dramatic turnaround in fortunes comes on Saturday when Rovers host fourth from bottom Soham Town Rangers. In a statement on their website, Rovers said the decision was not taken lightly before thanking Wilson for his efforts and backing their new boss.
Returning Rover: Iain O'Connell
The club said: "The Rovers Committee met tonight to discuss recent results and performances and agreed by majority decision to sack Keith Wilson as first team manager. It was not a decision taken lightly, with a must-win crunch game against Soham Town Rangers in just five days time.
"However, we felt the need to make a bold decision due to a run of results that has seen us record just two points from 30, drop to the bottom of the table and see the gap increase between us and second from bottom Wroxham.
"The Committee would like to thank Keith Wilson for his hard work and effort in what has been a very difficult time and wish him all the best for the future."
Explaining the move further and backing O'Connell to give their survival bid his best shot, the statement added: "Next, we wanted to move quickly to bring in a replacement and despite a small shortlist being drawn up, we felt one person stood out. We contacted Iain O'Connell immediately and he thankfully accepted.
"Whilst we agree that Iain has an extremely hard task to save the club from relegation, our decision was also based on who we felt could lead the charge for promotion from the Essex Senior League, should we be relegated this season. The club wish Iain all the best in his endeavours for the remaining ten games."
Images courtesy of www.gwrovers.com
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