Glentoran secured a first away win at Windsor Park since October 2022 as Declan Devine's men produced a stunning second-half to beat league leaders Linfield 3-1.

While they say form goes out the window in 'Big Two' derbies, the first such fixture of the campaign was playing out in wholly expected fashion with Joel Cooper opening the scoring for the hosts after eight minutes and the previously goal-shy Glens struggling to create opportunities.

Perhaps the only surprise was that David Healy's side, the most prolific in the Irish Premiership this season, failed to add to their tally before the break with Glentoran indebted to a string of saves from Daniel Gyollai.

But the men from the Oval were a changed side in the second half, both from the opening 45 minutes and from recent weeks, with goals from Jay Donnelly, Frankie Hvid and Cameron Palmer producing an incredible comeback to hand the Blues just their second defeat of the season.

Glentoran came into the contest struggling for goals, drawing blanks in six of their previous 10 league games including last weekend's 0-0 draw with Glenavon that drew a restless reaction from the locals in east Belfast.

They could ill afford, then, to go behind early to a sloppy goal. While defensive solidity has in the main been a strength this season - and new keeper Dan Gyollai was voted the club's player of the month for September - a mix up in their own box and a clumsy touch from skipper Marcus Kane allowed Cooper to smash the opener in off the crossbar.

With any plans to frustrate Linfield and hit the league leaders on the break having gone up in smoke before ten minutes had been played, Glentoran struggled to get a foothold in the contest and it felt as if Linfield were first to every bouncing ball.

The first-half was the Glens' season so far in microcosm - a dearth of opportunities beyond one header from the tireless James Singleton and having their keeper to thank that things weren't worse.

Gyollai had to be alert to stop Cooper doubling the lead while the former Glenavon man saw an audacious effort land on the top of the bar just before the half-hour mark.

When the visitors did get Dylan Connolly one-on-one with makeshift defender Chris Shields, the officials inexplicably awarded a goal-kick rather than a free-kick with Glentoran's complaints only tempered by Gyollai preventing the error looming larger with a save from Matthew Fitzpatrick up the other end moments after.

And the Glens were left to thank the Hungarian shotstopper once again moments before half-time when he got out to block Charlie Allen from close range.

But Declan Devine's side were a wholly different proposition in the second half.

Two corners in quick succession after the restart may not have seemed much, but it marked a considerable uptick in their application of pressure, and their improvement was rewarded by Donnelly's excellent finish from the edge of the box when teed up by Daniel Amos.

Confidence suddenly seemed to course through the visitors, even if Gyollai's save from Ethan McGee was a reminder of the work still to be done at the back.

Indeed, so keen were their players now to have a go, Donnelly and David Fisher attempted to strike the same bouncing ball.

Amos' set-piece deliveries were posing an increasing threat and, when centre-back Frankie Hvid powered one delivery past Chris Johns, the game had been completely turned on its head.

The 19-year-old, who scored the winning goal against Carrick Rangers when Glentoran last won away in the league, wheeled towards the visiting end in Windsor Park with even the celebrating supporters surely having doubted that such a comeback was in the offing.

As if to rub salt in the wounds for Linfield, the icing on the cake for Glentoran came when former Blues midfielder Cameron Palmer picked the pocket of Shields and slid the ball past Johns to make the points safe with ten minutes remaining.

As they wait to see whether they fall from top spot over the remainder of the Irish Premiership weekend, David Healy's side will rue the chances missed in that dominant first half. Glentoran, meanwhile, will hope this memorable derby win can kickstart their season.