A Grade One winner over 2m 1f and 2m 4f last season, Flemenstar kicked off what connections hope to be a Gold Cup season by taking on Big Zeb over two miles and despite reservations over his readiness and his ability to beat the three-time Fortria winner, Flemenstar supporters never had a moment's worry as he cruised to a comfortable seven-length victory.
The John Durkan Memorial Chase at Punchestown is now the next main target for Flemenstar, who was cut from 10/1 into 8/1 for the Cheltenham Gold Cup by bookmakers Boylesports.
Of course, the John Durkan could well set up a fascinating clash with dual Cheltenham Festival winner Sir Des Champs, although Willie Mullins remains tight-lipped over the seasonal debut of his leading Gold Cup contender.
It had been suggested that Flemenstar may go to England prior to Cheltenham in March, but without an entry in the King George, and Punchestown and then the Lexus at Leopardstown forming the main plan of attack at the minute, it would appear that should he be fit and well come March, then the Festival will be Flemenstar's first assault across the Irish Sea.
"It's two and a half miles next at Punchestown and then we'll have to think about three miles then. We are taking it step by step," said Casey.
Despite admitting that Flemenstar was only "about 80-per-cent fit," he added: "I'm not worrying about him as much this year - I slept well last night."
Andrew Lynch made all the running on the 10/11 favourite and as soon as he jumped the last safely, the majority of the healthy crowd at Navan were en route to catch a glimpse around the winners' enclosure.
"He's after strengthening up and I think he'll stay (three miles) on his breeding. He has a half-brother in England staying three miles."
Casey was in his usual flamboyant humour and joked: "I want some of the gate money," after the race as the crowds flocked around the parade ring.
Those in attendance also witnessed one of the biggest shocks on a racecourse this season as 1/7 shot Voler La Vedette was overturned on her seasonal bow by Oliver McKiernan's Whatuthink, who benefited from a superbly timed front-running ride by Tom Doyle.
The 10-year-old returned to hurdles for the Grade Two Lismullen Hurdle and reeled in the years to fend off the classy Colm Murphy-trained mare and oblige at odds of 25/1, booking his place at Leopardstown over Christmas in the process.
Four-year-old Sizing Rio also put in a very likeable performance to make every yard a winning one in the For Auction Novice Hurdle as Henry de Bromhead's youngster justified odds-on favouritism ahead of the late-finishing Ted Veale and that length-and-a-half win may prove more impressive than the bare form suggests.
The concluding bumper also saw the introduction of a very smart type as Ted Walsh's Champagne James made a winning racecourse debut in the colours of Barry Connell.