Royal Diamond justified short-priced favouritism for trainer-jockey Johnny Murtagh in the Listed Challenge Stakes at Leopardstown.
Last year's Irish St Leger winner, sent off at 5-4, soon opened up a big advantage in front and was well clear with a mile of the mile and three-quarters still to run.
Nothing ever seriously looked like narrowing the gap and Murtagh was able to ease his mount significantly close home, as Sir Ector ran on to take second.
Murtagh, recording his first Listed-race winner as a trainer, said: "He's improved a good bit from the Curragh (second to Ernest Hemingway in the Curragh Cup). I thought I had the race won there and I was surprised when they quickened past me.
"He came out of it really well and this was a nice race to go for as he likes Leopardstown.
"I had thought he was a Caulfield Cup/Melbourne Cup-type of horse and I might have to twist the owner's arm as he was thinking of going back for the Leger.
"He's a strong galloper. I have him pencilled in for the Ballyroan (Leopardstown, August 8) over a mile and half as I don't think he's slow.
"Mentally he's very well at the minute. The lads have done a great job keeping him sweet. He's getting older but he's every bit as enthusiastic as ever."
Tandem (6-1) let favourite-backers down in the Irish Lincolnshire at the start of the season, but Dermot Weld has given him plenty of time to recover from those exertions and he proved too strong in the valuable Irish Stallion Farms EBF "Nasrullah" Handicap.