Rangers narrowed the gap on Celtic to three points with a crucial victory at Motherwell.
The visitors took the lead at Fir Park when Liam Kelly palmed into his own net before Leon Balogun was sent off for a lunge on Dean Cornelius.
Scott Wright opened the scoring after the break and James Tavernier sealed the win from the penalty spot.
The pressure will be on Celtic when they travel to Ross County on Sunday, but they will have the chance to return the six-point lead when they face Rangers next weekend.
Motherwell will be disappointed they didn't make the most of having an extra man, especially after drawing level before the interval.
Since 2002, the Fir Park side has played 52 games, winning three points against the Ibrox club.
Motherwell would have been encouraged by the fact that Rangers lack of firepower would have given them encouragement.
The Fir Park club were without their talismanic front man in Kevin van Veen, who was suspended.
The former Queen of the South forward started well, leading the press with his pace as the home side snapped into challenges.
The hosts lacked cutting edge and it was the Rangers who had the first meaningful attack when Fashion Sakala's driving run resulted in Amad Diallo's goalbound effort being cleared.
The ball was bundled over the line minutes later when Tavernier's cross to the back post was headed by Goldson.
Kelly diverted the ball behind himself and saw it bounce over the line, as he tried to cut the effort out at the near post.
Motherwell looked for a way back into the game, but Tavernier's half volley was wide, while Slattery's long-distance shot was tipped round the post by Allan McGregor.
The game changed in a moment of recklessness. The referee had no choice but to dismiss the centre-back after the Rangers defender lunged over the ball.
The away side felt the game should have been evened up after Juhani Ojala flew into a challenge on Wright, but Walsh felt a booking sufficed.
Motherwell were level after seven minutes when Tierney nodded in a cross from the left.
Rangers were in need of half-time to arrive, and so it proved as they came out a more organised unit and regained the lead when another positive run from Sakala teed up Wright to drill an effort low into the far corner.
A penetrating run resulted in Sakala being clipped by Bevis Mugabi and he won a penalty. Kelly's 15th goal of the season was sent the wrong way by Tavernier.
Sakala plucked a Goldson ball out the air perfectly and should have finished off his performance when he faced Kelly.
The former Rangers keeper did well to stop the Zambian forward, who will have done his chances of starting the first leg of the playoffs no harm at all.
The character in Giovanni van Bronckhorst's Rangers side was highlighted by the back-to-back extra-time wins against Celtic and Braga.
It looked like three points would be hard to come by after Motherwell and Balogun drew. The heat on their rivals was turned up as the Dutch regrouped and reorganised their side to win.
If Celtic fail to win on Sunday, it will make the derby even more interesting.
The way Motherwell played second half, you would think it was them who had fewer men.
The first half was so promising that Graham Alexander's side ended it so promisingly, moving the ball with pace and purpose, but Rangers' second goal and quickfire penalty sucked any belief and positivity out of the hosts.
Motherwell manager Graham Alexander said he couldn't have been happier. We got a great response.
We got punished after we started with a passive mindset. It was hard to turn that around and the game slipped away from us.
The game plan had to be adjusted by the Rangers manager. We were in control of the game at the beginning.
We had to switch to a different way of playing because of the red card. It worked out well. You need to make sure that the players did what they were supposed to do.
The focus of Rangers will be on the first leg of the semi-finals of the Europa League on Thursday, before the Glasgow derby on Sunday.
Motherwell will be back in action next Saturday when they travel to Dundee United.
Formation 4-3-1-2.
5Mugabi14Ojala4Lamie3Carroll18Cornelius16Slattery27GossFormation 4-2-3-1.
2Tavernier6Goldson26Balogun31BarisicMotherwell won the match 1, Rangers 3.
Motherwell defeated Rangers in the second half.
An attempt was missed. Mark O'Hara's head from the centre of the box misses to the right. Dean Cornelius had a cross.
The Rangers' Cedric Itten had a foul.
The free kick was won by Slattery.
The Rangers' Cedric Itten had a foul.
In the defensive half, a free kick is won by a man.
The hand ball was thrown by the man.
An attempt was missed. Juhani Ojala's headed shot from the centre of the box misses to the left. A cross following a corner was assisted by Callum Slattery.
Corner in Motherwell. James Sands was the one who Conceded.
Corner in Motherwell. Conceded by Borna Barisic.
The Rangers had a substitution. Scott Wright was replaced by Cedric Itten.
The Rangers had a substitution. Steven Davis was replaced by Leon Thomson King.
Motherwell, Offside. Ricki Lamie tried a through ball, but Connor Shields caught it.
The attempt was saved. Fashion Sakala's left footed shot from the centre of the box is saved in the center of the goal. They were assisted by Connor Goldson.
James Sands of the Rangers had a foul.
The free kick was won by Dean Cornelius.
Fashion Sakala (Rangers).
Kaiyne Woolery won a free kick.
Foul by Joe Ayodele-Aribo.