Officials at Sandown racecourse were left relieved after threatened protests by Manchester United fans against John Magnier and JP McManus did not materialise.
Racing at Hereford on Friday was disrupted by a demonstration against the involvement of the Irish racing tycoons in the Old Trafford club.
There were fears the protests could spread to other higher-profile meetings, such as Sandown on Saturday, but there were no incidents reported.
Magnier's wife Sue owns Cheltenham Festival contender Rhinestone Cowboy - and his son, JP, rode the Jonjo O'Neill-trained gelding to victory in the Agfa Hurdle.
Friday's protest saw a group of about 30 people carrying banners declaring "Quit the horseplay Coolmore" and "United not for sale" going onto the track before the 1620 GMT race.
Magnier, owner of the Coolmore breeding empire, is in dispute with Ferguson over the stud rights to racehorse Rock of Gibraltar.
McManus, who together with Magnier holds a 25.49% stake in the club via their company Cubic Expression, was represented by Majestic Moonbeam in the beginners' chase.
The protesters strung their banners across the open ditch, causing a delay of 10 minutes before security staff escorted them from the track.
The group, calling themselves the Manchester Education Committee (MEC), threatened further protests at minor race meetings and a "spectacular" event.
In a statement, MEC said it has no interest in racing, but felt this was "the most effective way of applying pressure on Coolmore when it comes to the ownership and running of Manchester United".
 Ferguson is in dispute with Magnier and McManus |
It added: "This action will hopefully make Coolmore aware of the scope of the options open to the MEC. This was a small, relatively insignificant protest orchestrated by invitation only." Former champion jockey Peter Scudamore, who was at Hereford, told BBC Radio Five Live racing officials might have to tighten up security.
"It's a worry for the bigger races at Cheltenham and Sandown," he said.
"Mr Magnier has got a huge amount of horses, and Mr Magnier's son rides at Sandown. That would be a security worry, I would think."
The Independent Manchester United Supporters' Association has urged fans to attend race meetings where Magnier and McManus have runners "so they can leave them in no doubt about what they think of their attempts to destabilise the club".
The threat of action on racecourses first arose on Tuesday when McManus had runners at Taunton, but that meeting went ahead without any problems.