A match-up defined by its unpredictability and competiveness over the last few years has taken on a much more one-sided feel in the first half of this season.
Aberdeen followed up their 3-0 win at Pittodrie in September with another emphatic victory by the same scoreline.
The Dons stamped their authority on the match midway through the first half with goals from Adam Rooney and Kari Arnason and never looked like loosening their grip.
Saints’ cause certainly wasn’t helped by an injury to Murray Davidson that forced a tactical change and Steven MacLean passed up their best chance of the match at 2-0.
In the second half a comeback never looked likely and Ryan Christie’s deflected free-kick put the icing on the Aberdeen cake.
There were two changes in the Saints starting line-up from Saturday, with Steven MacLean and Paul Paton replacing Callum Hendry and Blair Alston.
Stefan Scougall was the Saints hero in Hamilton and he looked in the mood to build on his goal-scoring performance in this one.
The ball was fed to him on the right and after he skipped past his marker on the outside, his cut-back picked Davidson out 10 yards from goal. The midfielder’s initial shot was half-cleared and then Davidson dragged his second effort dragged it past the post.
Five minutes later the Dons had their first effort of note, with Graeme Shinnie’s shot in the box charged down.
It wasn’t much longer before they were ahead.
On 20 minutes Greg Stewart laid the ball into the path of Rooney and, with too much time and space from a St Johnstone point of view, the striker side-footed a finish past Zander Clark.
The bad news kept on coming for Saints as seconds after the re-start Davidson was on the turf in distress after he and Kenny McLean challenged for a ball in midfield. He was helped off the pitch for treatment but was unable to continue and Graham Cummins replaced him.
The Perth side were on the ropes and it should have been 2-0 just before the half-hour. Ryan Christie spotted Stevie May’s run through the middle and the former darling of the McDiarmid Park crowd smashed his first-time shot off the face of the bar.
On 33 minutes it was no great surprise when the second goal came and Saints were having to pull themselves up off the canvas.
May’s inswinging corner was meant for the front post but neither striker nor defender got a telling touch on it and the ball found its way to the back post where Arnason bundled it home from a couple of yards out.
Saints produced a decent response as the first half drew to a close. On 41 minutes a training ground corner ended up with MacLean getting a shot on the turn eight yards out that he would normally have given the keeper no chance with. On this occasion it was too close to Joe Lewis, who saved with his feet.
Then in stoppage time Lewis kept out a Michael O’Halloran 20-yarder.
Aberdeen were in no need of a helping hand but they got one anyway on 53 minutes when Cummins headed a ball back straight to Rooney, whose wild finish let his fellow Irishman off the hook.
The game was effectively ended as a contest a minute short of the hour.
David Wotherspoon conceded a free-kick in shooting distance but it was cruel luck for Saints that Christie’s set-piece took a deflection off the wall, wrong-footing Clark and giving him no chance.
Both managers made substitutions shortly after – May being replaced by Andrew Considine and Craig Thomson coming on for Scougall.
Tommy Wright’s third and final change was Blair Alston for Wotherspoon and Derek McInnes also completed his full set, with Stewart and Rooney making way for Gary Mackay-Steven and Nicky Maynard.
Aberdeen had no need to push for more goals but Shinnie – by now switched from left-back to centre-midfield – had an opportunity to let fly from 25 yards that he couldn’t resist. It didn’t trouble Clark, however.
With four minutes left Mackay-Steven did well to work space for himself in the box but the angle was too tight and Clark had his near post well covered as the left foot shot flew wide of it.
At the other end Richard Foster slashed an injury-time effort even wider and the full-time whistle blew seconds later.
St Johnstone – Clark, Tanser, Shaughnessy, Anderson, Davidson (Cummins 25), MacLean, Wotherspoon (Alston 77), O’Halloran, Paton, Foster, Scougall (Thomson 63). Subs not used – Mannus, McClean, Gordon, Craig.
Aberdeen – Lewis, Logan, O’Connor, Arnason, McKenna, Shinnie, McLean, Christie, Stewart (Mackay-Steven 72), May (Considine 60), Rooney (Maynard 77). Subs not used – Rogers, Reynolds, Ball, Wright.
Referee – Alan Muir
Attendance – 2,911