A real physical edge to this one with plenty of hits in the opening eight minutes.

A superb Paddy McBride two-pointer and a Ryan McQuillan score has brought Antrim back level after early Rory Grugan, Andrew Murnin and Callum O'Neill scores for the All-Ireland champions.

We're under way in west Belfast. We'll keep you updated on the major moments in this one.

BBC pundits Mickey Harte and Chrissy McKaigue agree with Antrim's decision to stand firm over today's venue.

McKaigue says hopefully Antrim can produce a performance that matches the "fight and resilience" they showed to have the game played at Corrigan Park.

John Haughey
BBC Sport NI at Corrigan Park

Looks like we're pretty much at the 4,000 capacity here in Corrigan Park as the throw-in is some 10 minutes away.

Over on the grass banks on the far side, it's hard to pick out any Saffron jerseys but there is a contingent of long-suffering Antrim football diehards in the covered stand here below me.

Both teams were out on the pitch before noon to begin their warm-ups so they should be ready for the off.

John Haughey
BBC Sport NI at Corrigan Park

It's not quite the blue sky conditions of last weekend's opener in Ballybofey but it's still a pleasant balmy day in west Belfast as Antrim aim to cause the mother of all Ulster SFC shocks by downing All-Ireland champions Armagh.

The forecast suggests that there is a slight chance of a shower before the end at Corrigan Park but hopefully the weather will behave for the mostly Armagh fans sitting down on the grass banks on the city side of the ground.

After a few warnings that the laptop could indeed be stationed on the lap today, the working conditions are perfectly accepted so we're ready for a game of football after all the rows about where the contest was going to be staged.

Image source, BBC Sport

Armagh's team includes only five - Barry McCambridge, Connaire Mackin, Rory Grugan, Tiernan Kelly and Andrew Murnin - of last July's All-Ireland final starting side.

It was due to be six but corner-back Paddy Burns is a late withdrawal as Gareth Murphy joins Tomas McCormack and Darragh McMullen in being handed a championship debut.

Burns will not be involved today as it also the case with Ciaran Mackin as Jarly Og Burns is drafted into midfield.

Ethan Rafferty replaces Blaine Hughes in goal with championship debutant Tomas McCormack, Ross McQuillan and Greg McCabe drafted into the defence.

All-Ireland winning captain and All-Star Aidan Forker, who was troubled by injury during the league campaign, is named on the bench.

Callum O'Neill and Burns form the midfield partnership with All-Ireland centrefield starters Niall Grimley and Ben Crealey not in the matchday squad.

Crealey is among four of the six Armagh All-Stars from last season who will not be involved with Rian O'Neill, Oisin Conaty and Conor Turbitt also missing from the 26-man squad.

Antrim make four changes from their side announced yesterday as Marc Jordan, Conor Stewart, Patrick Finnegan and Ronan Boyle are drafted into the side.

Jack Lenehan, Eunan Quinn, Niall Burns and Fionn Nagle drop to the bench.

Lenehan and Nagle will earn championship debuts if they are introduced.

Antrim: M Byrne; E McCabe, E Walsh, K Keenan; J McAuley, M Jordan, D McAleese; C Hand, C Stewart; P McBride, P Finnegan, R Boyle; R McQuillan, R McCann, D McEnhill.

Subs: L Mulholland, A Loughran, C Johnston, E Quinn, J McDonnell, J Morgan, J Lenehan, N Burns, P King, F Nagle, R Murray.

Armagh: E Rafferty; G Murphy, B McCambridge, T McCormack; R McQuillan, G McCabe, Connaire Mackin; C O'Neill, J Og Burns; D McMullen, R Grugan, P McGrane; T Kelly, A Murnin, S Campbell.

Substitutes: B Hughes, J Morgan, C Higgins, A Forker (capt), D Magee, C McConville, J Hall, S McPartlan, O O'Neill, S Conlon, C O'Hanlon

Image source, Inpho

Nearly 10 months on from bringing Sam Maguire home for the second time, Armagh are back in championship action.

The All-Ireland champions are in west Belfast this Saturday lunchtime as they begin their bid for a first Ulster title in 17 years against Antrim.

With doubts over whether Corrigan Park would host the game well and truly put to bed, Armagh hope to see off the Saffrons and move into the last four.

But can Antrim pull off an almighty shock? Last month, Andy McEntee's side were relegated to Division Four. On paper, Armagh look a safe bet, but stranger things have happened.

Stick around to see how this one pans out.