Tomahawk had his 2,000 Guineas odds cut to 10/1 after landing the Oak Lodge Sires Loughbrown Stakes in front of 7,013 sun-baked racegoers.
Last season's leading juvenile struck the front inside the final furlong to beat Abunawwas by 1L, with Chappel Cresent a further 3/4L adrift in third.
John Murtagh replaced Kieren Fallon, whose flight was delayed by fog, on Abunawwas but he was hit with a 2 day ban for careless riding following an incident with Former Senator (4th) over a furlong out.
'I wanted him to have an easy race after a couple of tough ones last season, and Mick was kind on him. He's a Guineas horse but we will decide which one in a few weeks after we see how some of the others come on,' said Aidan O'Brien.
O'Brien, who worked most of his stable stars after racing including High Chaparral, Hawk Wing and Brian Boru, also captured the opening 2yo maiden with Colossus.
The full-brother to Danehill Dancer was produced with a well-timed challenge by Kinane to beat Clock Tower by a comfortable 1/2L.
'He hadn't done alot at home, and Mick was tender on him. He has a lovely pedigree, and is a horse that should progress,' said O'Brien.
Fallon got his name on the scoresheet later when Wrong Key justified favouritism in the Listed Park Express Stakes, holding on by 1/2L from the strong finishing Miss Nashwan.
'That run will bring her on, and hopefully she can follow the same route as Rebelline last year with the Gladness Stakes and the Tattersalls Gold Cup likely targets,' said trainer Kevin Prendergast.
Harry Rogers got the season off to a great start when sending out Livadiya to take the featured ladbrokes.com Lincoln in tremendous style.
John Murtagh's mount swept to the front on the stands side inside the final furlong, and was eased in the closing stages to beat the always prominent Camargue by 3 1/2L.
'I will see how she comes out of this race, and she may go for a Listed race at Leopardstown next Saturday,' said the Ardee handler.
The jump jockeys came out on top of their Flat counterparts in the 12f Challenge handicap as Charlie Swan's mount Take Flite held off Cailin's Perk (Norman Williamson) by a neck.
Swan announced afterwards that this was his final ride in a Flat race, fuelling speculation that this may be his final season in the saddle.
Dermot Weld and Pat Smullen opened their accounts for the campaign when Colemanstown came out best in a blanket finish to the 7f handicap.
The Rosewell House trainer will be represented by One More Round over a mile in Dubai next Saturday, while he also outlined plans for Refuse To Bend.
'He will go for the 2,000 Guineas Trial at Leopardstown (April 13), and that will tell us if he is a Guineas or a Derby horse. He has done well over the winter but is a very laid back type.'
Miracle Ridge was given a fine ride by Helen Keohane in the sprint handicap, collaring Final Exam close home for a head victory.
Good Day Too (14/1-12/1) led home the cavalry charge under Paul Scallan in the concluding 30 runner maiden, with Tommy Stack's newcomer beating Maharib by 3/4L.
Alan Magee
