United are unbeaten in semi-finals against the Gunners, who themselves are unbeaten in finals involving the Red Devils. Overall, United have won six times and Arsenal five, with two matches drawn. But the Gunners won a penalty shoot-out against United, triggered when the 2005 final ended all-square after extra-time.
With the two clubs battling one another again for Premier League supremacy this season - and with both having something to prove after humbling 3-1 defeats in their respective last outings - interest ahead of the weekend's Old Trafford showdown is particularly acute.
To whet the appetite further, Goal.com UK looks back at five of the most memorable FA Cup meetings between two clubs whose 21 final triumphs (United 11 wins, Arsenal 10) make them the two most successful clubs in the history of the competition.
5. 2005 Final, Millennium Stadium
Arsenal 0-0 Manchester United
(aet, Arsenal won 5-4 on pens)
It's one of football's tiredest cliches that Arsenal haven't won a trophy since... well, this one six years ago. And they were outplayed for 120 minutes by Cup holders United, who saw Rio Ferdinand's 'goal' correctly disallowed, Wayne Rooney hit the post and Ruud van Nistelrooy's goal-bound effort kept out by Freddie Ljungberg on the line.
Arsenal, forced to play Dennis Bergkamp as a lone striker without the injured Thierry Henry, only managed their first shot on target in the seventh minute of extra-time. The goalless draw was the first in an FA Cup final since 1912, and forced the fixture's first penalty shoot-out. Jens Lehmann saved from Paul Scholes, while all the other spot-kicks were converted - including the decisive 10th, despatched by Gunners skipper Patrick Vieira.
4. 2004 Semi-final, Villa Park
Manchester Utd 1-0 Arsenal
Arsenal's unbeaten league record was maintained six days earlier in a 1-1 draw at Highbury, but at Villa Park United inflicted on the Gunners their first FA Cup defeat since May 2001. A typically tense and dramatic semi-final saw Arsenal twice strike the woodwork, have a penalty appeal for handball against future Gunner Mikael Silvestre rejected and dominate possession for lengthy spells, but fail to capitalise on their chances.
They paid the price when Scholes struck on 32 minutes, rifling a Ryan Giggs pass beyond Lehmann from 15 yards. With Wes Brown outstanding, United defended resolutely to deny Arsenal a fourth successive final, going on to beat Millwall and lift their 11th (and last) FA Cup.
3. 2003 Fifth round, Old Trafford
Manchester Utd 0-2 Arsenal
The intense rivalry between the teams was at its most bitter in 2003. United had won 2-0 at home two months earlier, but Arsenal still led the Premier League. A physical battle saw fouls galore, with referee Jeff Winter having almost every decision challenged by angry players.
Giggs uncharacteristically blazed over an open goal before Edu gave the visitors a 34th minute lead. Sylvain Wiltord added a decisive second seven minutes after the break, leaving Sir Alex Ferguson so incensed with the defeat that in the dressing room afterwards he kicked out a stray boot, unintentionally but infamously cutting David Beckham’s eyebrow.
2. 1999 Semi-final replay, Villa Park
Manchester Utd 2-1 Arsenal
Arsenal had won the Double the previous year; now United would complete the Treble, pipping the Gunners by a point in the league and beating them in the last FA Cup semi-final replay ever staged. Three days earlier the sides had drawn 0-0 in a game not without controversy. But for drama and excitement, the replay left it standing.
Beckham beat David Seaman from 20 yards on 17 minutes but Bergkamp equalised with a deflected shot on 68. The tie was tilting towards Arsenal as Nicolas Anelka had a goal disallowed, Roy Keane was sent off and Phil Neville tripped Ray Parlour to concede a penalty in stoppage time. But Peter Schmeichel saved Bergkamp's spot-kick superbly, refuelling United with fresh momentum for extra-time. Giggs intercepted Vieira's misplaced pass and ran on (and on), beating defender after defender before lashing a wondrous winning goal into the roof of Seaman's net.
1. 1979 Final, Wembley
Arsenal 3-2 Manchester Utd
The 'five-minute final' subjected fans of Terry Neill's Arsenal and Dave Sexton's United to an emotional roller-coaster in the stifling Wembley sun. Brian Talbot (a winner with Ipswich against Arsenal the previous year) put the Gunners ahead early on, and Frank Stapleton - later to join United - added a second before half-time with a trademark header from Liam Brady's cross.
Arsenal were coasting comfortably towards victory until the 86th minute, when Gordon McQueen pulled one back - and then, in the 88th, Sammy McIlroy sensationally jinked his way past two defenders and fired United level. With extra-time suddenly seeming inevitable and the force now indisputably with United, the inspirational Brady took the ball into enemy territory and fed Graham Rix, whose deep cross from the left was met by Alan Sunderland's run almost on the goal-line to restore Arsenal's lead and win the Cup in the last minute.