Rangers beat Celtic 1-0 at Celtic Park on Sunday, their second win over their Old Firm rivals in eight days. Ryan Naderi scored the only goal in the 33rd minute, and boos rang around the stadium, which was populated with home fans only.
The defeat was Celtic's first Scottish Premiership loss of the season. Martin O'Neill's side went into the game under the spotlight after two successive losses, including a 3-0 Scottish League Cup defeat by Rangers at Ibrox last Sunday.
Naderi's goal came from a James Penrice corner from the left, cleared to Kim Min-su, whose 20-yard drive was parried by goalkeeper Viljami Sinisalo to the Rangers striker, who quickly returned it into the net.
Rangers, managed by Derek McInnes, will feel they should have added to their lead after the break. Olwethu Makhanya fired in a second in the 74th minute but it was ruled out for handball.
Celtic are two points ahead of Rangers at the top of the table going into the international break, with more pressure on O'Neill.
Due to a ticket allocation spat between the two city rivals which saw the authorities step in, there were only Rangers fans inside Ibrox last week and only Celtic supporters at Celtic Park.