Perth Glory coach Ian Ferguson has revealed he was reluctant to play super-sub Steven McGarry in Saturday night's 3-2 semi-final win over Wellington, fearing the Scotsman could suffer further damage to his injured knee.McGarry's place in the side was thrown into doubt on the eve of the match after he collided heavily with goalkeeper Danny Vukovic in a training mishap.Scans cleared McGarry of any serious damage, but Ferguson was worried the midfielder's knee might not hold up under the intense pressure of a cut-throat semi-final.McGarry was desperate to play and Ferguson eventually made a compromise, dropping the 32-year-old from the starting line-up but giving him a place on the bench.The move proved to be a masterstroke, with McGarry playing a key role after coming on in the 70th minute.Glory were 2-1 down at the time, but were back on level terms just two minutes later courtesy of a well-placed strike from Billy Mehmet, who replaced McGarry in the starting line-up.Substitute defender Todd Howarth sealed the win in extra time, with his goal in the 112th minute sending Perth through to their first ever A-League preliminary final.But while Howarth proved to be the ultimate hero, Ferguson was full of praise for the tireless work of McGarry."He still had a little bit of swelling in his knee and I really didn't want to play him," Ferguson said."If we could have rested him and got through this game (without him) it would have been great."But we had no choice. He's been such an influential player for us this season. And he wanted to play."I felt it wasn't right to throw him in there in case we damaged his knee any more, but he was quite willing to take that gamble to sit on the bench."McGarry has played a critical role in Perth's revival this season, combining beautifully with striker Shane Smeltz in a 4-2-3-1 set-up.But after Mehmet's strong performance against the Phoenix, Ferguson admitted he faced a tough decision on the selection front.Since the start of 2012, Glory have won 11 games, drawn two and lost just three to become one of the form teams of the competition.But while Glory were in a state of euphoria on Saturday night, it was heartbreak for the Phoenix, who threatened to steal the match after second-half goals to Chris Greenacre and Manny Muscat gave them a surprise lead.Wellington's loss ended the playing career of club stalwart Tim Brown, who has retired in order to complete a Masters degree in management."He's addressed the players and all the staff. He's very emotional," Phoenix coach Ricki Herbert said."He's been the stalwart of the club; a foundation player."He's somebody we've all grown to know and respect. I wish him all the best."