Aidan O'Brien's horses are coming to the boil just in time for a tilt at the late-season's biggest prizes and the Ballydoyle squad struck on the opening day of York's prestigious Ebor meeting with a one-two in the Daily Telegraph Great Voltigeur Stakes.

Powerscourt and Brian Boru may both head for the St Leger at Doncaster next month after coming home clear of their rivals in the Group Two contest.

Brian Boru, ridden by Jamie Spencer, appeared to strike the front 150 yards from the finish, but Powerscourt and stable jockey Michael Kinane rallied to regain the advantage close home and score by a neck.

Favourite Hawk Flyer finished a further two and a half lengths back in third place.

''They have both run well and they could both come back to Doncaster, but there is the Irish Leger to consider,'' O'Brien said.

''Powerscourt didn't run until the Irish Derby but he was a good sixth and then he came back and won a conditions race to help give him some confidence.

''He has shown plenty of class at home and we didn't think there would be much between them here. We have always thought he was a very good performer.

''I probably made a few moves early in the season with him which I shouldn't have done. But he is definitely going the right way again now.

''It might be that over the extra distance Brian Boru could reverse the form.''

Bookmakers were divided over which of the pair to give the nod in revised betting for the final British Classic.

Paddy Power and the Tote prefer the claims of Powerscourt, with Coral favouring Brian Boru. But Bet365 offer stand-out prices of 5-1 and 6-1 respectively.

O'Brien and Kinane nearly struck again in the following Acomb Stakes, but Spencer had his revenge as Celtic Cat was just unable to reel in the David Loder-trained winner, Rule Of Law.

Spencer struck for home early in the straight and his mount stayed on bravely to take the Listed prize by a neck.

''That was a good performance,'' said Loder. ''He posted a decent time when he won his maiden here and we thought he would go well again.

''He is crying out for a mile and fitted the conditions nicely. He will probably go for something like the Royal Lodge.''

Bollin Eric gave the home side a warmly-welcomed winner in the Weatherbys Insurance Lonsdale Stakes as he showed his class with an emphatic victory.

Trained at Malton by Tim Easterby, the four-year-old was always swinging along on the bridle under Kevin Darley as Persian Punch adopted his customary position at the head of the field.

But dropped back to this two-mile trip, Persian Punch was unable to dominate in the way he normally does and faded back into fourth place.

Meanwhile, it was Zindabad who took up the advantage from Persian Punch and Jardines Lookout two furlongs out, but all the time Darley was looking confident aboard the 7-4 favourite.

With over a furlong to run, Bollin Eric kicked for home and the response was immediate. The winner stayed on throughout the final stages to hold Cover Up - who edged the runner-up spot from Zindabad by a short-head - for a two-length victory.

''I couldn't be more pleased,'' said Easterby as the horse scored for the first time since last year's St Leger.

''He has been running well all year and he deserved this. He is not just a stayer, he is a very good horse.

''Hopefully he will stay in training next year. I will have to talk to the owner.''

Darley paid tribute to his mount, who gave him his first British Classic success when taking the St Leger.

''He has been finding it a bit tough with a Group One penalty but he is never out of the frame,'' the rider said.

''He was just different class today and he left them for dead. He seems to be improving at the end of the season, just like he did last year.

''Persian Punch set the race up for me perfectly.''

Mark Johnston admitted to being disappointed at the performance of Zindabad.

''He seemed to get the trip all right but he is just not running to his best,'' he said.

Plans for the gelding will depend upon a change of ownership that could take place in the coming days