Nigeria international Efe Ambrose says Celtic will raise their game when they host Spartak Moscow on Wednesday night in the Champions League. <br /><br />Lately, the Glasgow giants are struggling for form in their home games, and have failed to win at Celtic Park since October 30.<br /><br />''Wednesday night is a Champions League game which we know we have to win to get a place in the last 16 because we are not counting on Barcelona to do the job for us.<br /><br />"We have to do that at Celtic Park. I believe the atmosphere will be different to the one against Arbroath.We have been playing well outside Celtic Park and winning games so I don't really know what is going on at home.<br /><br />"We are all disappointed. It has been quite long now without a (domestic) victory at home,'' Ambrose was quoted as saying by <i>heraldscotland.com.</i><br /><br />Efe Ambrose has suited up four times in the Champions League for Celtic.<br />