For their part, the Glasgow outfit were limiting Zenit to long range efforts and an Anatoly Tymoschuk drive and an Alexander Anyukov half-volley were easily dealt with by goalkeeper Neil Alexander.
Steve Jennings headed home and Lukas Jutkiewicz scored from the spot after Neil Alexander challenged Murphy.
Chris Millar had Saints' best efforts, the midfielder forcing a save from Neil Alexander in each half.
The second half was tense with Celtic's Fraser Forster saving from Steven Whittaker and Rangers keeper Neil Alexander denying Ledley.
Marcus Berg had an effort saved by Neil Alexander and Marcelo headed wide as PSV pressed for a first-half opener.
McGregor has missed Rangers' last three matches with Neil Alexander keeping goal in the wins over Motherwell, Partick Thistle and Hibernian.
United composed themselves and Paul Dixon's whipped cross found David Robertson, whose downward header was claimed by Rangers goalkeeper Neil Alexander.
David Clarkson found time and space in the box and cracked a right-footed swerving shot which Neil Alexander palmed round the post.
Martin Jorgensen fired straight at Neil Alexander in the Gers goal before Nacho Novo chipped over from 40 yards as Rangers improved in the second half.
Smith remained coy about his choice of goalkeeper, with Neil Alexander having been in possession of the jersey as Rangers clinched a league and Scottish Cup double.
Lafferty was stretchered off midway through the half, with Diouf coming on, before Neil Alexander kept the game alive by diving to push away Toivonen's curling effort from 20 yards.
The closest Fiorentina came to breaking the deadlock was when Adrian Mutu drilled in a late effort from 30 yards, but the Romanian was denied by an excellent save from Neil Alexander.
Neil Alexander started in goal in place of regular first choice Allan McGregor with the former expected to feature in this month's Co-operative Insurance Cup final against Celtic, as is customary for that competition.
Rangers goalkeeper Neil Alexander was then called into action when Brahim Hemdani lost possession just outside the box and the ball broke to Aleksandr Anyukov whose smart shot was initially fumbled and then held by Alexander.
However, the home keeper Neil Alexander, a surprise inclusion for the dropped Allan McGregor, didn't have a save to make until the start of the second half when he rushed to gather at the feet of Clarkson.
Roeder opted to utilise the experience of Dion Dublin up front and the former Manchester United striker almost put his side in front on seven minutes but was denied by a brilliant save from keeper Neil Alexander.
应用推荐