Derek McInnes has urged his Rangers team to find a killer touch in front of goal after a nerve-shredding victory over St Mirren.Rangers claimed a fourth win on the bounce thanks to a dramatic late winner from substitute Bojan Miovski, ensuring they remain five points behind Celtic in the title race.But they wasted several gilt-edged chances in a dominant first half and were so nearly made to pay for their profligacy as St Mirren came roaring back after half-time.The Buddies had a brilliant chance to take the lead at 0-0 when Fraser Taylor was through one-on-one, only to be denied by an excellent save from Ivor Pandur.McInnes insisted it was a crime that his team did not go in at least one or two goals ahead at the break, such was their superiority, and claimed the game should have been out of sight by that point.But, now heading into a blockbuster Old Firm double-header against Celtic, the Rangers boss has told his players to sharpen up in attack. An exasperated Derek McInnes watches his Rangers side struggle from the sidelines‘I thought we got what we deserved,’ said McInnes. ‘Granted, St Mirren had a 20-minute period in the second half when they were better than us.‘They played with a bit more belief and came after us and we were guilty of so many poor decisions. We were so reluctant to play forward quickly and invited them on to us with their press.‘But I thought the performance for the first hour was really strong, particularly the first half, where we absolutely battered St Mirren.‘We need to learn to kill teams when we have periods like that. But there’s absolutely no question we deserved to win the game in the end.‘I was really pleased with the performance. But, at 0-0, as an opposition manager, I’ve been in that position before at Ibrox.‘When you’ve been put through the wringer and you know you haven’t been punished for it, it does give you power and belief that you can get something from it.‘But I think that the team that had the better chances and played the better football ultimately won the game. We just need to be more clinical.‘There are obviously loads we have to improve on, but we have to keep winning while we are looking for those. We were guilty of not passing forward and it can’t always be about pretty patterns of play. North Macedonian striker Bojan Miovski knocks the ball past St Mirren keeper Jacob Chapman‘We obviously have a huge game on Sunday now. This should give the players and the fans a real boost. I think you saw that with the scenes at the end.’Miovski would be fifth-choice striker at Rangers if everyone was fit, but he came off the bench last night to score the winner with a lovely dinked finish.Indeed, it looked likely that the North Macedonian striker was on his way out of the club towards the end of the transfer window.‘It is just typical of football that a few weeks ago Bojan would have seemed so far out of it,’ said McInnes.‘He’s seen [Ryan] Naderi and [Youssef] Chermiti be big-money signings for the club and he knows, when you come to a club like Rangers, there’s going to be competition.‘But, when you actually strip it back, his goals per minutes in the Premiership is top class. It’s up there with Lawrence Shankland.‘So I was delighted when I inherited someone like Bojan who knows his way about the Scottish Premiership and is a goalscorer and, played in the right manner and with the right partner, is capable of scoring goals.’ Miovski shows what his winning goal means to him so soon after fearing he was leaving IbroxMcInnes also confirmed that Shankland will now undergo surgery today on the hamstring injury he picked up last weekend.And, in another blow, he also revealed that Daisuke Yokota will miss the next two to three months due to surgery on a groin issue.Yokota and Shankland will be operated on in London, with McInnes adding: ‘I think the surgeon is getting two for one.‘It’s unfortunate for Yokota. He’s torn the muscle off the tendon in his groin. It’ll probably be about two or three months unfortunately.’