Portadown suffered a first defeat of the Championship campaign as two goals in three second-half minutes by Niall Grace set Institute on the path to full points with a 2-1 win.
Home form is considered key for Niall Currie’s squad in pursuit of promotion and an immediate return to the Premiership but Institute held the upper hand overall with an assured performance.
The Ports’ late push was sparked by substitutes Adam Salley and scorer Kevin Amuneke but it proved too little, too late as Institute grabbed the glory.
Grace popped up with headers in quick succession off set-piece moves as Portadown followed up the previous week’s 1-1 draw away to PSNI with a defeat to end the club’s unbeaten start to the season.
It handed Institute a welcome lift off the back of flood damage to the club’s Drumahoe home and a 6-1 loss to Ballyclare Comrades.
Grace was on hand with the decisive touch inside a packed penalty area to convert Aaron Harkin’s cross and the scorer doubled his tally soon after with continued aerial success.
Amuneke made his mark by guiding home a cross from Salley on 78 minutes which sparked some late home pressure but without any overall reward.