Top-scoring winger Richie Lane and Munster prop Stephen Archer broke through for those decisive tries, notching a bonus point for Brian Walsh's men in the process.

Lane slotted a fourth minute penalty to move the visitors ahead, but centre Rob Keogh replied with a brace of penalties for Blackrock.

Both sides were reduced to 14 men following sin-binnings for Blackrock winger Dave Rowan and Peter O'Mahony of Cork Con for an off-the-ball skirmish.

But the loss of former Ireland Under-20 captain O'Mahony failed to deter the Leesiders who were back in front by the 23rd minute, thanks to a second Lane penalty and a Darragh Lyons try.

Out-half Lyons jinked his way through the Blackrock defence before crashing over the try-line, with good work from prop Martin Gately in the build-up.

Lane missed the conversion and a subsequent penalty kick, and the momentum swung back to Blackrock as centre Brendan Macken passed for flanker Alex Dunlop to go over unchallenged for 'Rock's opening try.

Keogh's successful conversion edged Blackrock ahead at 13-11, but Cork Con took control before the interval. Team captain Frank Cogan snatched an injury-time try in the right corner, with Lane adding the extras for an 18-13 turnaround.

Blackrock, who won this corresponding fixture 10-3 last season, were five points to the good by the hour mark. Full-back Niall Morris grabbed a try and Keogh landed two more place-kicks.

Morris' 57th-minute try came after a powerful burst forward from Dunlop, and while Morris had to scoop up a loose pass, he still had enough pace and power to make the line.

The hosts were hoping to give new coach Andy Wood a winning league debut at Stradbrook, but Cork Con had the better of the closing 10 minutes with wily winger Cronan Healy playing a key role.

Scorers: Blackrock College: Tries: Alex Dunlop, Niall Morris; Cons: Rob Keogh 2; Pens: Rob Keogh 3

Cork Constitution: Tries: Darragh Lyons, Frank Cogan, Richie Lane, Stephen Archer; Con: Richie Lane; Pens: Richie Lane 3

BLACKROCK COLLEGE: Niall Morris; Andrew Conway, Brendan Macken, Rob Keogh, David Rowan; Leon Ellison, Conor Crowley; Johnny Barretto, Cian Culleton, Kyle Cahill, Alex Dunlop, Des Dillon, Mick Noone, Barry Kelly, Mick Carroll.

Replacements used: Alan MacGinty for Ellison, Ben Prescott for Cahill, Paul Graham for Carroll (all half-time), Ryan Fisher for Culleton (59 mins).

CORK CONSTITUTION: Sean Scanlon; Richie Lane, Tom Gleeson, Simon Zebo, Cronan Healy; Darragh Lyons, Duncan Williams; Martin Gately, Robert Quinn, Stephen Archer, Brian Hayes, Ian Nagle, Billy Holland, Peter O'Mahony, Frank Cogan.

Replacements used: Michael O'Leary for Quinn (51 mins), Gareth Murray for Gately (64).

Referee: Simon McDowell (IRFU)