The draw leaves all four teams in the play-off berths separated by just one point heading into next Saturday's final round of regular season games with Ospreys, Glasgow Warriors and Munster all level on 70 points with the Ulstermen just a point behind with the race to a top-two finish and an all-important home semi-final still wide open.

Munster had looked to have sealed a remarkable victory at Ravenhill for the first time since October 2010 when Keith Earls scored a 77th minute try in a see-saw contest to send the visitors into a 23-16 lead, just minutes after Ulster forward Iain Henderson had been sent off for foul play.

Ian Keatley missed the conversion from the right touchline and with it the chance to put the match beyond Ulster's reach and the home side made the most of the opportunity, going upfield to get over the line with substitute Paul Marshall scoring in the corner with the match clock showing 80 minutes and 48 seconds.

It was up to Jackson to hold his nerve and his kicked from the left touchline sailed between the posts to send a sold-out stadium into raptures.

A draw was an apt reflection of a match played for the most part in sunshine on a hard, fast surface conducive to running rugby. Ulster did the lions' share of that but it was Munster who showed greater street smarts with a dominant pack.

The first half saw Ulster creating half chances without troubling Munster, who defended resolutely and astutely, absorbing pressure and then waiting for the home side to make a mistake, often through poor handling.

It was Munster wing Keith Earls who had the first real sniff of the tryline, capitalising on yet another stray pass on halfway and kicking ahead, racing past Ulster hooker Rory Best and getting his foot twice more on the ball only to be foiled over the line by some excellent covering pressure by Iain Henderson, the Ireland forward showing great athleticism to catch Earls at the crucial moment and force a Munster knock on in the act of touching down.

That proved to be Munster's only chance of a try in the opening half but they were making inroads via the boot of fly-half Ian Keatley who kicked the visitors into a 9-0 lead with three penalties in the opening 37 minutes.

That left plenty of time for Ulster to finally click, though, first Paddy Jackson slotting a penalty won at a scrum, which had previously been dominated by Munster.

With a minute to go, Ulster completely turned the game on its head, Rory Best catching Paul O'Connell's knockback from the restart, feeding the ball to Henderson whose carry and offload down the right wing provided the perfect handover to Tommy Bowe who scythed through two Munster defenders as he cut in off his wing and raced free for a try.

Jackson converted and for the first time in the game Ulster moved in front at 10-9 on the stroke of half-time.

A Jackson penalty opened the half as Ulster continued on the front foot but then the Munster pack rumbled back into action.

A Keatley penalty on 54 minutes closed the gap to 13-12 and the Munster pressure maintained as their scrum regained the ascendancy, twice in short succession stamping their authority to send Ulster into reverse, providing a penalty in front of the posts on a plate for Keatley to kick the visitors back in front.

Munster went further ahead with Keatley's sixth penalty of the afternoon before Jackson struck back to close the gap to 16-18 with 10 minutes to play.

Henderson's moment of recklessness, adjudged to have cleared out at a ruck with his head leading into the chest of Ronan O'Mahony, gave Munster hope of a rare win in Belfast when Earls struck as the reds moved it wide having mauled strongly from a lineout.

But it was Jackson and Ulster who had one last decisive say in the matter.

ULSTER: L Ludik; T Bowe, J Payne, D Cave (S McCloskey, 56), P Nelson (P Marshall, 64); P Jackson, R Pienaar; C Black (A Warwick, 62), R Best - captain, W Herbst, (B Ross, 51); D Tuohy, F van der Merwe; I Henderson, C Henry, R Wilson (R Diack, 30).

Red card: Henderson (73)

Replacements not used: R Herring, C Ross, I Humphreys.

MUNSTER: F Jones; K Earls, A Smith, D Hurley, S Zebo (R O'Mahony, 27); I Keatley, C Murray; D Kilcoyne (J Ryan, 48), E Guinazu, S Archer (BJ Botha, 48); D Ryan, P O'Connell; P O'Mahony – captain, T O'Donnell (J O'Donoghue, 3), CJ Stander.

Replacements not used: D Casey, B Holland, D Williams, JJ Hanrahan.

Referee: Nigel Owens (Wales)