It signalled Hearts were serious about topping the Ibrox side and denying them their third title on the bounce.
Playing in front of the biggest crowd of his career, that match was also the kind of high-profile contest that had lured the Swede to the second tier of Scottish football in the first place.
Although his preceding spell at Crystal Palace had not gone as anticipated, injury and registration issues consigning him to a season in the reserves, he was not convinced that the Scottish Championship would be the wisest or most rewarding next step.
But discovering that the Gorgie club would be up against two of the only other three Scottish sides he had even heard of was an inducement.
“One of the reasons I came to the club was that we would be playing Rangers and Hibs four times a season at least. As a player, you want to play big games. And when you know you are going to play Rangers and Hibs then it is good – it is a motivator.”
Today’s match against Rangers is the first of three big games wedged into the final run of matches. Hearts travel to Easter Road to face Hibs in the final capital derby of the season next Sunday and wrap up their Championship season with a home match against Stuart McCall’s men and the trophy presentation on 2 May.
“It has gone beyond my expectations,” says the 24-year-old striker.
“It was a big thinker for me because I could have played in the top division in Sweden. But I really felt for what Robbie and Craig said though, and I thought I would opt for Hearts.
“When you get a good feeling in your stomach you go with it. This is my first title and it is good.”
Promotion featured prominently in that meeting with manager Robbie Neilson and director of football Craig Levein but it’s unlikely any of them anticipated having the job done and dusted so early in the campaign.
“But I always had faith that we would go up a division [after speaking to the men in charge],” said Sow. “That was the target and it always feels good when you accomplish something.”
A torn thigh muscle, sustained in the October head-to-head with Hibs, sidelined Sow for a chunk of the season and forced him to revise his scoring targets. With games running out, he knows he won’t make his pre-season goal of 20-plus but, with 12 so far this term to top the club charts, he is still in with a chance of finishing the campaign as the free-scoring side’s leading scorer as they race to compile a significant total before the end of the season.
“We still have a lot to prove against Rangers and a lot more to play for. We still want to score more goals and get over the 100 line and you want to look back at the season and say ‘remember the time we won the league by 30 points’.” Currently on 86 goals, they know that both targets are definitely attainable.
Signed on a three-year deal, a decent finish to the season will set Sow up for his shot at the top tier next term, when his manager expects him to cope well with the higher standard of opposition and still find the net.
“But he has still to prove it, like they all have to,” said Neilson. “They all have to prove that they are good enough for the top level. Osman has been fantastic.
“He is quite a calm guy, laid back but great to have about the club. He is very humble and I think he is happy to be here.”
But while Neilson has one eye on next season, happy to capitalise on the head start gained in the transfer market thanks to the club’s ability to seal the title so early in proceedings, he wants his men to remain focused on the here and now and maintain their level of intensity until the final kick of the ball.
“Without a doubt we want that,” he said. “All season we have had that and we want to continue that, which is why going to Ibrox and then Easter Road within the space of a week is great for us. We also have Rangers on the last game of the season so that gives us a bit of focus.
“Rangers have definitely picked up since Stuart [McCall] came in and they are well organised and they have changed their shape a couple of times, so I’m expecting a difficult game. I have watched their recent games and they are working really hard and there’s a bit of commitment about them at the moment. They seem to have the bit between their teeth again.”
Hearts showed that kind of intent on the very opening day, though, which is why all others have spent the season playing catch-up and scrapping for a play-off place.