(CNN) -- Rangers took a significant step towards the Scottish Premier League title when Steven Davis scored the only goal of the final Old Firm derby of the season against Celtic at Ibrox.
Steven Davis slides in to send Rangers two points clear in the Scottish Premier League title race.
Victory saw Rangers move two points clear of their Glasgow rivals with just three games to go.
The only goal came after 37 minutes when recalled Kenny Miller whipped the ball into the goalmouth for Davis to slide into the back of the net from inside the six-yard box.
Davis had threatened early on with a long-range shot that flashed across the face of goal while Miller's overhead kick was also off target as Celtic came under pressure.
The visitors responded through Shunsuke Nakamura whose well struck free kick was tipped over by goalkeeper Neil Alexander while Celtic claimed they should have had a penalty after 32 minutes.
The referee ignored their appeals when Scott McDonald went to ground under pressure as he was about to shoot -- and Davis rubbed salt into their wounds.
Apart from scoring, he made a great defensive contribution when he cleared a Jan Vennegoor of Hesselink header off the line just before the break.
The big Dutchman had a chance to make amends in the second half when he threw himself in front of an Andreas Hinkel cross only to see his another header smothered.
Rangers, however, should have increased their advantage, but Boyd squandered their two best chances.