The Premier League's greatest rivalry begins a new chapter on Saturday evening as Louis van Gaal faces Arsenal for the first time as Manchester United manager.
The two clubs spent the late 1990s and early 2000s at each other's throats, literally at times, as they battled for the biggest prizes in the English game.
However, they are no longer the major forces in the Premier League and this season are competing for a place in the top four rather than a title which Arsene Wenger concedes is already Chelsea's to lose.
The sixth-placed Gunners are 12 points behind the Blues in the table, but one point and one spot above United heading into a meeting of the division's two most injury-hit sides at the Emirates Stadium.
United could field a star-studded XI of fitness doubts, although David de Gea is expected to play despite dislocating his finger on Spain duty, while Angel di Maria should also shake off an international-break knock.
The prognosis on Daley Blind is worse, although better than first feared, with the Dutchman poised for six weeks on the sidelines with knee ligament damage sustained in Holland's 6-0 win over Latvia.
Radamel Falcao, Michael Carrick, Luke Shaw, and Rafael are all doubts, while Marcos Rojo, Jonny Evans and Phil Jones are definitely missing. Chris Smalling returns from suspension to ease the defensive concerns.
With options limited, Van Gaal may be forced into recalling Ander Herrera in midfield. The Spaniard, who joined in a £29m deal from Athletic Bilbao in the summer, has not played for the Red Devils in almost two months and United are already prepared to offload him in January, according to reports.
Juan Mata has also been linked with an Old Trafford exit, but he too may get a start at the expense of Adnan Januzaj after coming off the bench to score the winner against Crystal Palace a fortnight ago.
It was a memorable week for Wayne Rooney, who moved to within three of Sir Bobby Charlton's England goalscoring record, and he will support former Gunners captain Robin van Persie in attack.
Arsenal have been boosted by the surprise news that Olivier Giroud is available following his broken leg. The French striker has been out for three months, but has recovered much quicker than anticipated.
Although he will be included in the squad this weekend, it is unlikely that Giroud will deny Danny Welbeck the chance to play against the club which he left to join the Gunners on transfer deadline day.
The 23-year-old, who made 142 appearances for United after coming through their academy, is benefiting from regular football in a centre-forward role and is impressing for both club and country.
Welbeck netted twice as England came from behind to beat Slovenia 3-1 at Wembley last Saturday, in a Euro 2016 qualifier in which Arsenal teammate Jack Wilshere was named man of the match.
Alex Oxlade-Chamberlain also scored for the Three Lions in midweek, but both he and fit-again Theo Walcott will likely be on the bench, with Santi Cazorla and 12-goal Alexis Sanchez more probable starters.
Sanchez netted his sixth goal in four games in the 2-1 defeat to Swansea City last time out. Mesut Ozil, Laurent Koscielny Mikel Arteta, Mathieu Debuchy, David Ospina missed the visit to Wales and remain injured.
Arsenal:
Form in Premier League: DLDWWL
Form in all competitions: DWWWDL
Possible starting lineup: Szczesny; Chambers, Mertesacker, Monreal, Gibbs; Flamini, Ramsey; Cazorla, Wilshere, Sanchez; Welbeck
Man United:
Recent form : WWDDLW
Possible starting lineup: De Gea; Valencia, Smalling, Blackett, Shaw; Fellaini, Herrera; Januzaj, Rooney, Mata, Van Persie
Sports Mole says: 2-1
