Former Manchester United manager Alex Ferguson celebrated a notable hat-trick on the opening day of the Aintree Grand National meeting on Thursday, with three of his horses winning in Grade One races. The 79-year-old Scot said it was his "best day in racing" after Protektorat, Monmiral and the star of the show, Clan Des Obeaux, all triumphed at the racecourse near Liverpool. Ferguson is no stranger to success in racing. Rock of Gibraltar won 10 of his 13 starts in 2001 and 2002, including both the English and Irish 2000 Guineas. "Always great to score a hat-trick in Liverpool, they won't be very pleased," said a masked Ferguson, who co-owns the winning horses. The former United boss had a fierce rivalry with Liverpool during his 27-year reign at Old Trafford. "That's the best day I've had in my time in racing, which is about 20 years or so. "It is different to when I was managing my football teams – I was in control of what was going to happen on the pitch, but I'm not in control of that [on the racetrack] as the trainer [Paul Nicholls] does all of that and as an owner you hope it goes well. "You do get the same excitement when you win big races like that as it does get you very excited." Clan Des Obeaux, after his victory in the Bowl Chase, is the most successful jumps horse Ferguson has had an interest in. Ferguson will be back on Saturday as he has an outsider in the Grand National, Give Me A Copper, who is bidding to succeed two-time winner Tiger Roll.