Dante Polvara is on for Kristers Tobers. The Latvian centre-back was making his Dons debut, but it lasts just 66 minutes.

Polvara and Sivert Nilsen - two centre-midfielders - are now Aberdeen's back pair.

Jamie McGrath is also on for Leighton Clarkson in midfield.

Oscar Cortes almost makes an instant impact with a fierce low drive, but St Johnstone goalkeeper Andy Fisher is up to the task with a strong hand to deny the winger.

A yellow card now for James Penrice, as the Hearts left-back comes from behind to wipe out Duk on the touchline.

Elton Kabangu is being readied in the away dugout. The new signing will replace Musa Drammeh as he makes his debut for the visitors.

Oscar Cortes and Cyriel Dessers replace Vaclav Cerny and Hamza Igamane as Rangers manager Philippe Clement makes changes up front - perhaps with one eye on midweek against Aberdeen.

Willie Miller
Former Aberdeen captain on BBC Sportsound

A little bit of pressure from the home side - giving the fans something to cheer about, because they haven't had much so far this afternoon.

Tyrone Smith
BBC Scotland at Pittodrie Stadium

The game is opening up a little bit now at Pittodrie, with play starting to go from end to end.

But it is still crying out for a lot more quality.

Pittodrie rises to its feet as the ball falls to Duk on the edge of the penalty area, but the forward's low driven shot is well blocked.

However, it's got the stands singing again after falling quiet in the first 15 minutes of this second half.

Billy Dodds
Former Scotland striker on Sportsound

Look at St Johnstone's set-up, they look more secure.

They're frustrating Rangers now. I can't believe they never started like this.

Image source, SNS

Two little chances for Hearts. Musa Drammeh's header is blocked at close range before Cammy Devlin's cross/shot rises over the bar.

A little better from the visitors. Remember, it's been nine years since they've won at Pittodrie.

Tyrone Smith
BBC Scotland at Pittodrie

Not much to report from Pittodrie in this second half.

With Duk replacing Kevin Nisbet up top for Aberdeen, they will be hoping he can bring a bit of energy and spark that has been lacking in the striking area so far.

Boos and howls of derision at Ibrox as some supporters stage a walkout, which was mooted pre-match but, unfortunately for the Rangers players, coincided with St Johnstone's goal.

It would seem those who are staying put are none too impressed and want all fans to get behind the team.

Kevin Nisbet is replaced with Duk and the Cape Verde international moving into the number nine position for Aberdeen.

We've not seen him in that role for a while.

It's been a really slow start to the second-half from both sides, but it's Hearts with the first half-chance.

A short corner is worked to Blair Spittal on the edge of the box and he whips a shot that goes a yard or two over.

Better from St Johnstone - they must have been listening to Billy Dodds. Mackenzie Kirk cuts inside and his shot is deflected wide.

Billy Dodds
Former Scotland striker on Sportsound

I think Simo Valakari will learn from today.

You can't go to places, when you are bottom of the league, like Celtic Park and Ibrox and play open, attacking football or you will get a doin'.

Some nice interplay between Mohamed Diomande and Hamza Igamane ends with the former's volley being deflected wide.

Rangers try to keep the pressure on at the corner, but Saints clear their lines.

No signs that those half-time Saints changes have changed the direction of traffic.

St Johnstone start this season half with two substitutes on.

Aaron Essel has been replaced with left-back Barry Douglas, while captain Nicky Clark has not re-appeared, with winger Taylor Steven his replacement.

Back to the action and Rangers winger Vaclav Cerny is denied by goalkeeper Andy Fisher.

We're off again at Ibrox and Pittodrie.

A couple of St Johnstone changes at half time and we'll bring you details of those shortly.