MANCHESTER, England - It wasn't so long ago that Arsenal vs. Manchester United was one of the marquee matches in the English Premier League, a fixture that went a long way to deciding which team won the title.

Now, it pits two sides struggling to even get in the top four.

Arsenal is sixth and 20-time champion United is seventh heading into Saturday's game at Emirates Stadium, with both clubs having had a tough start to the season mainly because of injury problems and suspect defending.

They have already been cut adrift by Chelsea, which is the unbeaten leader after 11 games and showing the kind of form that is making pundits wonder whether it can go through the season without losing.

Here are some things to know about the upcoming matches after the international break:

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UNITED'S INJURIES: United manager Louis van Gaal is counting the cost of the recent batch of international games, with defender Luke Shaw (unspecified) and midfielder Daley Blind (knee) joining an already-lengthy injury list at Old Trafford.

Angel Di Maria and Michael Carrick should shrug off knocks and be fit to play against Arsenal, while goalkeeper David de Gea is available despite dislocating his finger on duty with Spain.

Van Gaal has been blighted by injuries, his defence regularly short of its best players and Colombia striker Radamel Falcao starting just three times following his expensive loan move from Monaco. Falcao will miss at least two more weeks because of a calf injury.

United said on Thursday that 12 members of its squad had been carrying injuries.

Van Gaal's side hasn't won any of its five away matches in the league.

WELBECK FACES OLD TEAM: Danny Welbeck will look to show United was wrong to sell him on transfer deadline day this summer when he lines up for Arsenal against his old club for the first time.

The England striker has five goals in 12 games for Arsenal since leaving his boyhood team, where he rarely got a start or was played out of position on the left wing.

"Personally I have been surprised by his technical capacity, the way he understands the game, his work rate," Arsenal midfielder Mikel Arteta said. "I rate him more now than I used to, and this is a good sign because normally the opposite is true when you watch a player on a daily basis."

While Welbeck and fellow summer signing Alexis Sanchez, who has six goals in his last four league starts, have been the positives for Arsenal, the defence remains a worry for manager Arsene Wenger.

Arsenal has thrown away a lead in its last two matches, drawing 3-3 against Anderlecht in the Champions League after being 3-0 ahead, and conceding two late goals to lose 2-1 at Swansea in the Premier League.

NO STOPPING CHELSEA: Chelsea is turning the title race into a procession, with only surprising Southampton in touching distance of the leader ahead of its home match against West Bromwich Albion on Saturday.

Chelsea holds a four-point lead and has played arguably its four toughest matches — away games at Everton, Liverpool, and the two Manchester clubs — without losing. Its biggest title rival, defending champion Man City, is eight points behind in third.

"We don't have the title in the bag," goalkeeper Thibaut Courtois said. "We are trying to win every game, but there is still a long way to win the title."

Top-scorer Diego Costa should be refreshed after being rested by Spain over the international break.

LIVERPOOL'S ATTACKING WOES: Liverpool's strikeforce was the main reason why the team finished second in the league last season. This time round, it's proving Liverpool's biggest issue.

In the absence of the injured Daniel Sturridge since early September, Mario Balotelli, Rickie Lambert and Fabio Borini — the other three strikers in the squad — have not scored between them in the league.

Like Arsenal and Man United, Liverpool's objective is simply finishing in the top four to secure a place in the Champions League, but it is in 11th place.

Balotelli injured his hamstring on international duty with Italy and is a doubt for Liverpool's match at Crystal Palace on Sunday.

ELSEWHERE: Looking to maintain its stunning start, Southampton goes for a fifth straight win when it visits Aston Villa on Monday. Man City hosts Swansea while fourth-place West Ham is away to Everton.