Manchester United's trip to the Emirates on Sunday is the big Premier League clash of the weekend, with both sides needing all three points for very different reasons.Louis van Gaal's Red Devils will return to the top of the league with victory, leapfrogging arch rivals Manchester City in the process. Arsenal, on the other hand, could at least go level with United in second place with a win and it would serve as the perfect way to bounce back from a hugely disappointing Champions League defeat at home to Olympiakos in mid-week.Man United are by far the form side out of the two, and will be hoping mega-money deadline day signing Anthony Martial can continue his superb start to life in England. Arsenal's Alexis Sanchez returned to his formidable best in front of goal last week as he scored a hat-trick in the Gunners' 5-2 away win at Leicester, and he'll be expected to recreate such form on Sunday afternoon.It's always difficult to predict which way these games will go, but we've spoken to expert fans from both clubs (@GoonerGimli & @UnitedHeaven_) to see what they think ahead of one of the biggest Premier League games of the season so far. It's fair to say one Arsenal player is an unlikely member on a certain United fan's wish list.Here's what they had to say...

1. Who will be the key players for both sides?

2. What will the final score be?

3. Which opposition player would you like most at your club?