Rangers reduced Celtic's lead at the top of the table to one point with an unconvincing 1-0 victory at Kilmarnock yesterday.
Shota Arveladze supplied the goal after 16 minutes, controlling a cross by Alan Hutton before drilling his shot past goalkeeper Graeme Smith.
It was a welcome boost for the Glasgow club who were bundled out of Europe in midweek with a 2-0 home defeat by Auxerre in the UEFA Cup.
Rangers have 46 points from 19 games, with champions Celtic, who also laboured to a 1-0 win against Dundee United on Saturday, on 47.
"It was vital we won this game after the misery of midweek," said Rangers manager Alex McLeish.
"It was a difficult away game today but we got a good goal from Shota Averladze and we would have liked to have built on that.
"I thought we were reasonably in control of the game, but at 1-0 you can never really relax."
Chris Sutton, meanwhile, insists Celtic are not losing their dominant grip over the rest of Scottish football. The Parkhead side could only manage to find the back of the net once on Saturday when Sutton headed in the only goal of the game in the first half, despite a barrage of chances.
A mixture of stubborn defending from the Tannadice side and poor finishing from Celtic meant they were desperately holding on for the win as United pushed forward in the final minutes of the game.
But Sutton denies their inability to kill off a team struggling at the wrong end of the table is cause for alarm, because he believes the non-Old Firm clubs have always been tough opposition.
"It's always been difficult," he said. "Looking back over the years that I've been up here, there was one year when we had four games that we won in the last minute by the odd goal. They were obviously vital wins at the time and you just have to grind it out.
"We kept a clean-sheet and the three points are important for us."
But manager Martin O'Neill admits he was worried by the lack of goals.
He said: "When we didn't get the second goal it's obviously a concern as you can see from previous games from ourselves and other teams, and finishing the game off was difficult for us today so I'm pleased we won.
"I would like us to have scored the second goal and we could have relaxed a bit but it wasn't going to be and Dundee United were fresh from an excellent win themselves last week."
