A first-half David McAllister own goal was all that separated the sides in a tight affair at Mourneview Park.
Coleraine hammered Glentoran 4-1 at the Showgrounds with James McLaughlin scoring twice.
David Jeffrey's Ballymena United ran out easy 4-1 winners away to Carrick Rangers to move into the top half of the table.
Relive the action from Friday's Premiership matches
Despite suffering their first defeat of the season, Ards are still tied on points at the top of the table.
There were few clear chances in the game, with defences on top before McAllister nodded past keeper Aaron Hogg and into his own net after 17 minutes of play.
Crusaders and Linfield can overtake the joint leaders if they win their respective games on Saturday.
The Bannsiders put four goals past Glentoran, who continued their disappointing start to the league campaign.
Coleraine took the lead after eight minutes when referee Mervyn Smith pointed to the penalty spot when Elliott Morris was adjudged to have brought down James McLaughlin despite getting a strong palm on the ball.
Neil McCafferty made no mistake from the spot by slotting past Morris, although the Glentoran keeper may feel aggrieved that he wasn't ready to face the kick.
Three goals in nine minutes assured Coleraine of the points. Darren McCauley tucked home after being played through by Rodney Brown, before McLaughlin drove the ball home from the edge of the penalty area three minutes later.
McLaughlin grabbed his second just after the hour mark to wrap up the victory, before Jonathan Smith fired home after some good work from Nacho Novo to give Glentoran a consolation goal.
Defeat for Glentoran means that the East Belfast side slip into the bottom half of the table, while Coleraine's first victory of the season carries Oran Kearney's side up to eighth.
Ballymena responded from last weekend's defeat by Ards in perfect style, putting four goals past Carrick Rangers.
Allan Jenkins opened the scoring, slamming home from a corner after just three minutes.
Cathair Friel doubled Ballymena's advantage on 22 minutes by heading in from a Tony Kane free-kick.
Carrick Rangers were provided with a glimmer of hope when Alan Blayney picked up a back-pass and Gareth McKeown's free-kick rebounded off the United wall for Nathan Hanley to make no mistake from the rebound.
Jonny McMurray scored Ballymena's goal of the evening, letting fire with a fine 30-yard strike which flew over Simon Steele in the Carrick goal.  Ballymena completed the rout when former Carrick player Conor McCloskey slotted home just after the hour mark.

The service for cousins dual Irish-US citizen Ashley Donohoe, 22, and Olivia Burke, 21, from Dublin, was taking place in Sonoma.
The bodies of four other Irish students will be repatriated on an Aer Lingus flight to Dublin on Saturday night.
They are due to arrive at Dublin Airport on Sunday morning.
On Friday night the relatives of LorcÃ¡n Miller, Eimear Walsh, Eoghan Culligan, and Niccolai (Nick) Schuster received their bodies for the first time at a joint service in St Columba's Church in Oakland, California.
Their bodies lay in repose in open caskets until around 22:00 local time.
After Saturday's joint funeral service for Ashley Donohoe and Olivia Burke, Ms Burke's remains will be flown home to Ireland on Sunday evening.
The balcony collapsed during a 21st birthday party in the early hours of Tuesday in the city of Berkeley.
Five of the six people who died were Irish students based in the US as part of a work exchange programme.
The victims were:
Meanwhile, the conditions of two of the people who were injured in the Berkeley balcony collapse have improved.
Conor Flynn and Jack Halpin are being cared for at the John Muir Medical Centre in Walnut Creek.
Hospital pastor Fr Michael Gillen described the pair as inspirational and said they should make a full recovery.
Investigations continue into why the fourth-floor balcony collapsed.
Engineers say water damage may have caused the structure to give way.
Authorities said 13 people were on the balcony when it collapsed.
A book of condolence is to be opened at Belfast City Hall on Monday.
Glenavon beat Ards 1-0 to join the newly promoted Co Down side at the Premiership summit.
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A joint funeral mass is being held in California for two of the six students killed in an apartment balcony collapse in Berkeley on Monday night.