It was a day of contrasting fortunes for Rory McIlroy and Pádraig Harrington in the second round of the Honda Classic at Palm Beach Gardens as the defending champion rallied to shoot a 68, while the world number three slumped to a second consecutive 72 that will see him miss the cut for the second year in a row.

Having been just two shots off the lead at the end of the first round Shane Lowry also endured a frustrating second day in Florida – beginning his round with two bogeys on the 10th and 11th holes before a double bogey on the 14th.

He would recover with two birdies in his next four holes and his back nine started much more consistently too - four straight pars - before undoing that good work with two more bogeys on the the fifth and sixth, and another on the ninth. Leaving him one over par for the tournament.

Harrington sits at one over par going into the weekend, nine shots off leader Rickie Fowler who carded another 66 to lead by one from Jimmy Walker.

The Californian’s sizzling early season form shows no signs of abating as he continues to push the narrative of the ‘Big Three’ becoming the ‘Big Four’ in world golf.

A bogey-free round, punctuated by birdies at the 16th, third, sixth and ninth saw him top the leaderboard after the morning groupings had completed their rounds.

Of that supposed ‘Big Four’ Fowler will be the only one in action at the weekend after McIlroy’s struggles continued, while Jordan Spieth and Jason Day both elected to take a week off.

Starting on the 10th, the 2012 Honda Classic champion looked primed to burst out of the blocks and move up to leaderboard with an early birdie at the par four 12th.

But after finding the water with his tee shot on the par three 15th, McIlroy’s wedge from the drop zone landed short of the pin and spun back onto the fringe. Two putts later and it would be a double bogey.

A pitch in left of the green on the 16th for birdie saw him card a level par opening nine of 35, however it all began to unravel on the par four first - his 10th. After rolling his birdie effort six feet by he would miss the return putt to drop a shot.

A birdie on the par five third looked to have settled the ship but the decisive blow came on the fifth.

After his tee shot embedded in the bank of the lake just left of the green on the par three, matters would got when he chunked his pitch into the hazard.

A drop and a failed up-and-down saw a triple bogey six marked down on his scorecard and, with it, any hopes of making the weekend.

Playing alongside the world number three, Harrington looked set for a weekend off himself after a bogey on his opening hole was followed by a double bogey on the 11th when his approach shot found one of the multitude of lakes around the PGA National layout.

But the grinding qualities of the Dubliner were on show in all their glory as he rallied to card a superb seven birdies in his next 11 holes.

After picking up a shot at the 12th he made it two in a row with a three at the 13th.

A holed birdie putt from the fringe on the par three 15th was followed by a searing five iron approach shot at the par four 16th that would see him pick up another shot as he rolled it in from 20 feet.

Birdies on the only two par fives on the course – the 18th and third – were followed up by a three at the par four fourth and suddenly the defending champion was inside the top 15.

However a scrappy finish would see him drop shots at the seventh and ninth to sit one over par, just inside the top 40 going into the weekend.

Meanwhile, birdies at the 12th and 17th saw Graeme McDowell card a second round 69 to sit at level par with two rounds to go.