Manchester United are ready to battle Manchester City for the signature of Arsenal forward Alexis Sanchez in January. The Chilean is available on a free transfer next summer, so bids of around £30 million are expected to persuade him to move earlier, but which club should he join? And should he snub both to stay at the Emirates?
Our club correspondents make their case for Sanchez to arrive, or stay put.
MAN CITY: Become one of the best in world and win trophies
If Sanchez still has footballing ambitions in England, his only realistic move is to Manchester City. The Chilean has never won the Premier League and by switching to the Etihad Stadium he is all-but guaranteeing himself a winner's medal in May.
With this expensively-assembled squad, Pep Guardiola's side will be challenging for the biggest trophies in Europe every season, but the same can't be said at Arsenal, and who knows with Manchester United under Jose Mourinho.
But there will be no shortcuts at City for Sanchez. In a squad bulging with quality, he'll have to compete against the best in Europe (both opposition and his own teammates) and, in a year when he will miss out on the World Cup, it will be a real opportunity to make his mark as one of the best players on the planet.
Guardiola has always been a fan of Sanchez since he took him to Barcelona and not many players can turn down the best coach in the world, who once again this season has shown he can make great footballers even better.
Guardiola is secure in his job and has a clear strategy moving forward, while there always seems to be uncertainty surrounding the futures of Arsene Wenger and Mourinho. The latter is back to his old ways of picking fights -- even criticising his own players if he thinks it's the right thing to do -- and that environment is not the most attractive proposition for a player who can have his pick of sides.
At 29, Sanchez's next move may well be the last big one he makes. If he wants to cap a brilliant career with a late flourish of success, City are his best bet. -- Jonathan Smith.
MAN UNITED: Come and be one of the "Untouchables"
It will be difficult for United to convince Alexis Sanchez to choose Old Trafford, as City offer the chance to work with a manager he has had success under before (Guardiola) and, probably, a Premier League winners medal in May.
Money is not an issue; United can offer Sanchez the same wage packet he would get at City. They can, though, offer him prominence.
United need a player like Sanchez more than City. Guardiola has already got Sergio Aguero, Gabriel Jesus, Leroy Sane, Raheem Sterling, David Silva, Kevin De Bruyne and Bernardo Silva competing for places in the front five. It means Sanchez would not necessarily be guaranteed to start every week.
That would be different at Old Trafford. Jose Mourinho does not like to rest Romelu Lukaku, but no one else starts every week. Marcus Rashford and Anthony Martial have shared the job on the left while Henrikh Mkhitaryan, Juan Mata and Jesse Lingard have all been in and out of the team at different points.
Sanchez would immediately be one of the "Untouchables." If it's trophies that matter to the Chilean, he would probably have to wait until next season to challenge for the biggest ones if he signs for United. One of the key questions is whether he is willing to wait that long. -- Rob Dawson.
ARSENAL: Erm... the weather in London is better than up north...
At this stage, pleading for Sanchez to stay at Arsenal is a bit of a lost cause -- especially since he has good reasons for leaving.
Why turn down more money -- including a massive signing bonus -- and a chance to play for a better team that's virtually guaranteed to win the Premier League? The glory of fighting for a top-four spot and the Europa League title just doesn't have the same ring to it. Neither does the prospect of playing alongside Alex Iwobi and Danny Welbeck instead of Kevin De Bruyne and Sergio Aguero.
Aside from the old "loyalty" line, there just isn't any sporting argument that makes sense. Sorry, Gunners' fans, but the fact is Arsenal have failed to build a team around Sanchez and Mesut Ozil that's good enough for their own standards.
London has its charms, though, compared to Manchester. The weather is nicer. We've all seen on Instagram how much his dogs Atom and Humber love running around in Hampstead Heath. If that's not enough to turn down millions of pounds and the promise of multiple trophies, then there's not much more to add really. -- Mattias Karen.