Sydney coach Paul Roos has refused to be drawn into a new umpiring controversy in the wake of his team's nail-biting four-point loss to West Coast on Friday night.The game was an outstanding example of hard, uncompromising man-on-man football, and a great start to the AFL finals series.But with 12 minutes remaining in the last term, a crucial free-kick gave West Coast a goal when the ball was taken off Brett Kirk and given to Tyson Stenglein - who calmly slotted it from 50 metres to bring the deficit down to just three points - after Leo Barry was penalised for shepherding the man-on-the-mark.Then, with 28 minutes gone, a blatant trip on Adam Goodes from David Wirrpunda was missed 35 metres out. The ball spilled free and West Coast cleared the ball to the wing.After the match, Roos just laughed when questioned about the incidents."How do you expect me to answer a question like that?," he said.But when asked if he'd ever seen a free kick like it (the Stenglein incident): "Never."None-the-less, it was just an outstanding game of football, with punishing one-on-one contests all over the ground all night, and Roos said going so close in Perth was a good sign."I think everyone in football would have suggested that the West Coast trip is the toughest one at the moment - all due respect to Adelaide, Adelaide is the top side - so to come across here, and give ourselves every chance to win and just for it to swing on a couple of little things that could have gone either way, we've got to take some positives out of it."Sydney held a 14-point lead going in to the final term, but was out-scored five goals to two, and Roos said West Coast simply took their chances better."It was probably some of our silly mistakes, and a free kick, that I think they got their goals from, and that swung the momentum a bit."It just ebbed-and-flowed - we got a late goal and were still a chance to win."Without looking at the tape, it's probably hard to make a full assessment of it, but look, it's probably just like the rest of the game - it ebbed-and-flowed and certainly in the last quarter, they took their chances and we didn't."Roos said that despite the loss, getting his side up for next week's do-or-die against either Geelong or Melbourne shouldn't be a problem."Look, that's hard to tell. Think you realise when you get to this stage that you either win and have a weekend off, or you lose and you've got to play again next week."I'm sure the players will have thought of both scenarios going into the game, and unfortunately we took a four-point loss and we play again next week."We're still in the finals, we're still a chance."