A blustery autumn day with regular bouts of heavy showers made for a dogged scrap up front, the kind of game that did not allow 'Rock to exercise their trademark quick-running rugby.
However, their forwards, spurred on by seasoned pros like Des Dillon and Trevor Hogan, proved a point and showed that they could win matches the tough way.
A gritty but hugely exciting encounter looked to be finishing up as an anti-climactic 3-3 draw, but in the 75th minute the alert 'Rock scrum half David Moore took full advantage of a tiring Cork Con defence to dive over the line from two metres out.
Cork Con are entitled to be very disappointed that they were not victors as they put in a solid performance, dealing well with blustery conditions.
Ultimately though, their defence hit a lull late in the second half and they allowed 'Rock to threaten their try-line.
Speaking after the match, Blackrock forwards coach Barry Gibney gave deserved praise to his pack.
"Given the team we have, the pack always has to go out and prove themselves," he told IrishRugby.ie.
"A lot of people just write about Blackrock's backs but in good conditions the pack gives them good ball.
"But it was the massive work rate, a huge effort by the pack.
"Days like that are won up front, so long as we could hold onto the ball, keep up the pressure and put Con in the situation where they were forced to go away from a kicking game and run it towards the end, then we would have advantage."
This victory sees Blackrock continue their unbeaten run and retain their place at the top of Division 1A, but the win also showed another dimension to their competitive nature and puts them as strong contenders to go all the way in this fiercely competitive league.
Gibney added: "We've been in dogfights before but we might have lost more dogfights than we've won in the past.
"You can say that we'd prefer to win outright but I'd like to think we can do it both ways. We can play a tight game and we play it up front if we have to."
For Cork Con coach Brian Walsh, there was a lot that his team could take out of the tough contest. But, in the end, his side could not keep their concentration in the final quarter when the match was eventually decided.
"I thought we did an extremely good job in the first half, we did what we had to do," he said.
"We won most of the skirmishes and looked to have the better appetite. I think we just went through a little lull in the second half, we slipped off one or two tackles, that's a concentration thing and we struggled to get territory back."
But he admitted that coming into the match, his side were facing into a huge task.
"The league this year is the league of small margins and coming up to 'Rock with them on the back of a good victory against Garryowen, it was always going to be difficult."
This was the second time this season that Cork Con have lost in the dying moments of a match, the first coming against Dolphin in their opening Division 1A clash, so this defeat will come as a big setback to their title aspirations.
However, credit must go to Walsh's charges who put up a great challenge against a strong 'Rock side and they will hope to get back to winning ways against Garryowen next week.
Click here for a full Blackrock College v Cork Constitution match report.