The Blues were the favourites to retain the Gibson Cup before a ball was kicked this season, but Glenn Ferguson's side put in a stirring performance to make an early dent in the title aspirations of his former club.
Jamie Davidson was the hero for the Sky Blues, scoring in either half to wrap up the victory.
His first came two minutes before half time, with Davidson hitting a fierce shot across keeper Alan Blayney and into the net.
Davidson doubled his tally 15 minutes from time as he kept his composure to slot low past Blayney to make it 2-0.
Elsewhere, top-flight newcomers Ballinamallard United didn't quite get off to a winning start in their Premiership opener, but they did manage to secure a share of the spoils with a 2-2 draw against Dungannon Swifts at Ferney Park.
Ryan Harper opened the scoring for the Swifts before Johnny Topley's header made it 2-0 in the 38th minute.
The Co Fermanagh side left it late to mount their comeback, but Andy Crawford capitalised on a defensive error to score his side's first goal in the top flight, before a superb injury-time goal by Chris Crawford straight from a corner ensured it finished all-square.
Glentoran, meanwhile, got their campaign off to a winning start with a 3-1 victory over Belfast rivals Donegal Celtic.
Jay Magee opened the Glens' account from the penalty spot after Jim O'Hanlon was fouled inside the area, and Andy Waterworth made it 2-0 with just 12 minutes on the clock.
DC got themselves back into the game with a Mark Miskimmin goal just before the break, but Jim O'Hanlon's 56th minute header helped to seal all three points for Eddie Patterson's side.
Coleraine got their campaign off to a winning start with a comprehensive victory over Crusaders at the Coleraine Showgrounds.
The Bannsiders went ahead early in the match when Curtis Allen floated the ball over Crues keeper Michael Doherty, and doubled their advantage in the 32nd minute when Paul Owens found the net.
It was skipper David Ogilvy who made it 3-0 with a rasping 30-yard free kick, with substitute David Rainey grabbing a consolation for Stephen Baxter's side three minutes from time.
Over at Shamrock Park, Portadown secured all three points with a 4-2 victory over Lisburn Distillery, although the Whites made Ronnie McFall's side work hard for the spoils.
Ryan Burns found the top corner with a 13th minute effort to set the Ports on their way, and Joe O'Neill doubled the hosts' advantage around the half-hour mark to give his side a two goal cushion at the break.
But, Tim McCann's side mounted a stirring second half comeback, with Johnny Harkens missing a penalty before goals from Jordan Forsythe and Michael Halliday got them back on terms with nine minutes to go.
However, it wasn't to be as late goals from Gary Breen and Jamie Tomelty wrapped up the win for Portadown.
Finally, a last-gasp winner from Chris Scannell saw Cliftonville come from behind to beat Glenavon 2-1 at Solitude.
IFA Premiership Results:
Ballinamallard United 2-2 Dungannon Swifts
Ballinamallard: Andy Crawford 63, Christopher Curran 90
Dungannon Swifts: Ryan Harpur 8, Johnny Topley 28
Ballymena United 2-0 Linfield
Ballymena: Jamie Davidson 45, 75
Cliftonville 2-1 Glenavon
Cliftonville: Liam Boyce 36, Chris Scannell 90
Glenavon: Sean McCashin 12
Coleraine 3-1 Crusaders
Coleraine: Curtis Allen 5, Paul Owens 32, David Ogilby 53
Crusaders: David Rainey 87
Glentoran 3-1 Donegal Celtic
Glentoran: Jay Magee 8, Andrew Waterworth 12, Jim O'Hanlon 57
Donegal Celtic: Mark Miskimmin 43
Portadown 4-2 Lisburn Distillery
Portadown: Ryan Burns 13, Joe McNeill 31, Garry Breen 88, Jamie Tomelty 90
Lisburn: Jordan Forsythe 73, Michael Halliday 81