Ronny Deila lauded his players for stretching their lead at the top of the Premiership with victory at St Mirren – then hit out at the state of pitches in Scotland . A James Forrest strike and Stefan Johansen ’ s penalty were enough to see off a spirited challenge by the bottom side as Celtic moved eight points clear of Aberdeen . But although pleased with the way his side stayed patient to win , Deila felt their cause wasn ’ t helped by the state of the Paisley surface . And he believes Scottish football will struggle to develop top players if there isn ’ t a drastic improvement in our pitches . Celtic manager Ronny Deila was impressed with his side 's performance against St Mirren on Friday night . ‘ It was a tough game , St Mirren were well organised and played very deep , ’ he said . ‘ They fought really hard and it was difficult to break them down . We had to be patient . The pitch was better than some others we ’ ve played on . But the pitches in Scotland are terrible . ‘ If you want to develop players and get passing football , it ’ s difficult when the ball is bouncing all the time . It ’ s much easier for the other teams to just sit behind the ball and try to break down our play . ‘ It ’ s better to play on an artificial surface than this . If they are watering artificial pitches and they are of the best quality , it ’ s totally different and much closer to European standards . James Forrest slides on his knees to celebrate scoring Celtic 's opening goal against St Mirren . ‘ If we are going to develop good young players , you need a good surface to play and train on . If not , you get fighters . If you want skills and technique , play on better surfaces . ‘ They are much better in Norway . Sixty per cent are artificial and the grass pitches are better as well because they don ’ t train there and there aren ’ t other teams playing on them . And we play in the summer . That ’ s the biggest thing . The pitch here might not look so bad but try to play on it. ’ TV pictures showed Leigh Griffiths eating a chocolate biscuit while sitting on the bench . But Deila , a strong advocate of fitness and conditioning , laughed it off . ‘ I think it was a carbo biscuit which is totally different ! I ’ ll have to check his weight tomorrow. ’ Celtic midfielder Stefan Johansen slots home from the penalty spot to secure his side 's 2-0 victory . Goalscorer Johansen believes there ’ s no stopping Celtic as they close in on a treble . ‘ It looks great for us now , ’ he said . ‘ I don ’ t think we ’ re unbeatable but there is a huge confidence in the team . ‘ We are starting to look fitter and have much more of the ball because we ’ re playing with a higher tempo . That ’ s the way the manager wants us to play . I said in the beginning when people were asking questions I was confident he would be a great and it ’ s starting to look that way. ’ Saints boss Gary Teale felt there were positives in defeat but wasn ’ t happy about the handball awarded against Viktor Genev for Celtic ’ s penalty . ‘ Was it ball to hand or hand to ball ? If they ’ re going to give penalties for things like that they need to give all of them in every single game. ’ Deila berated the state of pitches in Scotland and claimed it would be better to play on artificial surfaces .
Celtic beat St Mirren 2-0 to move 2 points clear at the top of the league . Ronny Deila praised his players for their patience in waiting for the win . Although pleased , he said the pitches in Scotland are 'terrible ' Deila believes it would be better to play on artificial pitches .