Rangers paid the price for some shoddy defending as they twice surrendered the lead and had to settle for a Champions League draw with Artmedia Bratislava.
Dado Prso headed the visitors in front early on but Balazs Borbely levelled after Rangers failed to clear a corner.
Steven Thompson's header put Rangers ahead again but a mix-up between Ronald Waterreus and Brahim Hemdani gifted the equaliser to Jan Kozak.
Peter Lovenkrands then missed an open goal with a header as Rangers pressed.
With Inter Milan beating Porto 2-1, the Italians lead the way on nine points, with Rangers and Artmedia four points adrift and both two clear of the Portuguese.
Rangers dominated much of the match and made the perfect start, surging into the lead after just three minutes.
A Hemdani free-kick was met at the back post by Sotirios Kyrgiakos and the Greek defender powered a header across goal for Prso to nod into the net from a yard out.
However, Artmedia were back on level terms just four minutes later when Rangers failed to clear a corner.
Blazej Vascak's delivery led to an untidy scramble in the box and the ball eventually broke to Borbely who slammed it home from close-range.
Rangers goalkeeper Waterreus then got a hand to fierce deflected drive from Ales Urbanek after a positive run from the home player.
Both sides were finding lots of room in attack and Thompson sent a smart curling shot on the turn narrowly wide.
Prso (right) put Rangers ahead after just three minutes
Waterreus held on to a 25 yard effort from Branislav Fodrek, while Fernando Ricksen and Lovenkrands also tried their luck from distance but did not trouble 'keeper Juraj Cobej.
Rangers were rewarded for their attacking endeavour with a fine goal shortly before the half-time break.
Ricksen and Prso worked a short corner and the Croatian striker's cross found Thompson who crashed in an impressive header.
Artmedia should have been level after 52 minutes when Julian Rodriguez was caught out trying to usher the ball for a goal-kick but Fodrek blasted his shot high and wide after Lukas Hartig had robbed the Rangers defender to set him up.
Soon after, a shot from Hartig flashed beyond Waterreus but Olivier Bernard was on the goal-line to clear.
Rangers were looking shaky in central defence and they were punished on the hour when Waterreus and Hemdani clattered into each other and the ball broke for Kozak to fire into an unguarded net from 20 yards.
The Ibrox side found a late burst of energy and Lovenkrands wasted a wonderful opportunity in the 82nd minute.
A Bernard delivery dipped down on to the crossbar and Ricksen was first to react - scooping the ball across goal - only to see the Danish winger head wide of an open goal from six yards.
Artmedia Bratislava: Cobej, Petras, Debnar, Durica, Urbanek, Vascak (Tchur 83), Kozak, Borbely, Fodrek, Obzera (Stano 87), Hartig (Halenar 73). Subs Not Used: Kamenar, Mikulic, Konecny, Burak.
Goals: Borbely 8, Kozak 59. Booked: Fodrek.
Rangers: Waterreus, Hutton, Kyrgiakos, Rodriguez, Bernard (Murray 90), Ricksen, Ferguson, Hemdani, Lovenkrands, Thompson (Jeffers 70), Prso. Subs Not Used: Klos, Andrews, Alex Rae, Burke, Namouchi.
Goals: Prso 3, Thompson 44. Booked: Kyrgiakos, Ferguson.
Ref: Florian Meyer (Germany)