There will be prettier games of rugby in this United Rugby Championship campaign, but what the first Interpro of the season lacked in quality, it made up for in tension.

Emotions were high at Thomond Park, five years to the day since the sudden death of head coach and Munster legend Anthony Foley, and marking the occasion with a win - by whatever means - was what mattered most to Munster.

They got there eventually, Diarmuid Barrion the unlikely hero as he squeezed over the line in the 79th minute to draw Munster level, Joey Carbery's conversion sealing a dramatic derby win.

It was a moment of redemption for the out-half, who seven minutes earlier had seen his kick charged down by Man of the Match Jack Carty for a try, a score which looked like it would it would seal a second consecutive Connacht win at Thomond Park.

Conditions didn't help the contest, with several hours of rain in Limerick on Saturday evening, and while it cleared by kickoff, the home side in particular struggled with their handling, which led to a scrappy, nervy derby in front of 17,192 supporters.

The game was barely 90 seconds old before Connacht had the chance to put something on the scoreboard, a clever move off their lineout bringing wing Mack Hansen infield, and after the Australian was finally tackled inside the 22, Beirne's penalty concession allowed Jack Carty to tap over the easiest of penalties.

As the game developed Munster looked the better team, but Carty added a second Connacht penalty on nine minutes when the home side were pinged for going off their feet.

Connacht seemed happy to soak up the pressure, causing Munster trouble on any of their entries to the 22 in the opening quarter. Indeed, they almost had a try on 23 minutes when Mack Hansen crossed the line following an incredible reflex volley and pass from O'Halloran, but the full-back's final pass was forward.

It was a major let off for Munster, but once again they couldn't take advantage of it, turning over possession deep in Connacht territory following a malfunctioning lineout.

The first half had been running at a constant simmer, with several minor scuffles testing the patience of referee Chris Busby, and a high tackle by former Munster man Sammy Arnold on Mike Haley drew the day's first yellow card on 33 minutes.

Following the script of the first half, the momentum was killed with a handling error.

And then, after 38 minutes and 43 seconds of frustration, Munster fired a shot out of nowhere.

After Haley had gained the initial yards on the right side of the pitch, Rory Scannell spotted a pod of heavies on the opposite wing, floating a left footed crossfield kick into the space.

Beirne briefly turned into Bergkamp as he cushioned the ball forward with his left foot, before sending it back out to the wing with his second chip as Cloete touched down.

Replays showed Beirne had been ahead of Scannell for the original kick, but the score stood as Carbery drained the conversion, making it 7-6 as the half time whistle blew.

Somehow Munster were in front. Somehow Connacht were behind.

It looked like it had been a game-changing moment when Munster dominated the early stages of the second half.

However, they had to settle for a Carbery penalty on 49 minutes, following nearly 10 minutes of dogged Connacht defence.

Conceding three points rather than seven was a mini-victory for Connacht, and just three minutes later they had regained their lead.

Winning a penalty close to the Munster line, they opted to tap-and-go, with the Munster defence committing too early, as number eight Paul Boyle somehow found a hole in red wall to score.

Carty's missed conversion made it 11-10 in Connacht's favour, but Munster responded well to regain the lead just before the hour mark, winning a penalty off the back of a strong maul, Carbery splicing the posts from the left side of the pitch.

It was becoming a battle of out-halves, and Carty ousted Carbery on 68 minutes, silencing Thomond Park.

A routine Munster scrum saw the ball make its way to Carbery on his own 22, but the Ireland international was far too casual as he prepared his clearing kick, Carty launching himself into the air to block the ball perfectly, and collecting it on the follow through to run in under the posts.

His simple conversion made is 18-13. Munster had nine minutes to turn it around.

There had been little to suggest they would over those previous 70-odd minutes, but when has that ever stopped Munster?

Camped on the Connacht line for phase after phase, hooker Diarmuid Barron eventually burrowed over the frontline, levelling the game and leaving a chance at redemption for Carbery.

His conversion, midway between the posts and the left touchline, was roared over by the Ballynanty end, a dramatic ending on an emotional night in Limerick.

Munster: Mike Haley; Andrew Conway, Keith Earls, Rory Scannell, Simon Zebo; Joey Carbery, Craig Casey; Dave Kilcoyne, Niall Scannell, John Ryan; Jean Kleyn, Tadhg Beirne; Peter O'Mahony (C), Chris Cloete, Gavin Coombes.

Replacements: Diarmuid Barron, Jeremy Loughman, Stephen Archer, Fineen Wycherley, Jack O'Donoghue, Neil Cronin, Jake Flannery, Dan Goggin.

Connacht: Tiernan O'Halloran; John Porch, Sammy Arnold, Bundee Aki, Mack Hansen; Jack Carty (capt), Caolin Blade; Matthew Burke, Dave Heffernan, Finlay Bealham; Niall Murray, Ultan Dillane; Cian Prendergast, Conor Oliver, Paul Boyle.

Replacements: Shane Delahunt, Greg McGrath, Jack Aungier, Eoghan Masterson, Abraham Papali'i, Kieran Marmion, Jarrad Butler, Tom Daly.

Referee: Chris Busby (IRFU).