Michael Dunlop secured a dominant win in Friday evening's red-flagged Open A Invitation race at the Cookstown 100 road races.The 37-year-old Ballymoney rider had built up an advantage of 9.4 seconds over runner-up Michael Sweeney when the race was halted on lap seven of nine and a result later declared.Riding his MD Racing BMW Superstock machine, Dunlop recorded a best lap speed of 91.322mph, marginally outside the lap record of 91.773 for the 2.1-mile Orritor circuit which he set last year.Manx rider Marcus Simpson was fourth, with Ballymoney's Darryl Tweed fifth and Paul Jordan from Magherafelt sixth.Dunlop was a late entry for the Cookstown Irish national meeting as he continues his preparations for the forthcoming North West 200 and Isle of Man TT international events, having taken part in the official test sessions at Oulton Park in Cheshire earlier this week.As well as competing in the Open and feature races, the 33-time TT winner is campaigning a Honda in the Moto3 class for the Burrows Engineering/RK Racing outfit run by former racer John Burrows.Earlier on Friday, Dunlop led the qualifying times for the Open class, ahead of Jordan and Sweeney.Jordan was fastest in Supersport qualifying on his Jackson Racing V2 Ducati as he made his first appearance at the county Tyrone circuit in four years.Tweed, Sweeney, Simpson and Keyes were next on the practice leaderboard.Dunlop was quickest of the Moto3s, almost three seconds faster than second-placed Dan Sayle, with Sweeney topping the Supertwins timesheets.Fifteen races are scheduled for Saturday, including a second Open A race, the feature race, a Supersport outing, the Supertwins event and a Moto3 class.'Last minute decision' to race at CookstownDunlop was a double winner at the Cookstown 100 12 months ago, winning the Supersport and feature races."It was a bit of a late, last minute thing," Dunlop told BBC Sport NI of his decision to compete this year."We are so busy and we weren't going to come as the 600 [Supersport bike] is stripped to bits to get ready for the North West 200 as it is just around the corner."I brought my Superstock. I like it and I like riding Cookstown. It has always been nice to ride around here and it is a good thing to get out and get a bit of racing done. The weather is lovely and that is half the battle."The biggest thing with the Stocker is that we haven't had much time on it so it gives it a chance to get an outing."Dunlop is enjoying a rare outing on a Moto3 bike."We had sort of done a gentleman's agreement, me and John Burrows, about riding his Moto3 months ago and I said if I was able to come, I would come and then I forgot clean about it."So, he called me again on Thursday and I was like 'aw, I forgot all about all about that!".Dunlop added that a degree of caution had to be exercised with his two biggest events of the season just around the corner."At the end of the day, it is about staying out of trouble a little bit with the NW 200 just around the corner and the TT just around the corner from that as well so we are at a stage that you have to just watch yourself."Jordan was pleased to be competing at the meeting for the first time since 2022."I've had a really good pre-season building up to it and I feel like I've stepped it up again from what we did last year, and we had a good year last year, so hopefully the momentum stays with me and we keep moving forward," he said.