In the worst kept secret of this transfer window, Alexis Sanchez moved to Manchester United from Arsenal in a swap deal with Henrikh Mkhitaryan on Monday night.

The 29-year-old Chile striker, who came close to joining Manchester City last summer, has signed what is believed to be a four-and-a-half-year contract that will make him the highest-paid player in the Premier League. It has been widely reported that Sanchez will earn a pre-tax salary of £500,000 ($695,000, 567,000 euros) a week. Armenia international winger Mkhitaryan, also 29, will head to the Emirates after he fell out of favour with United manager Jose Mourinho during 18 months at Old Trafford.

Even before it was finalised, the deal had the attention of the media and fans and when it was finally announced - with the Chilean playing the piano to boot - it was trending all over social media.

From stats to jokes and digs, Twitter was full of emotions at the rare swap deal between two top clubs. Here’s a look

Some number-crunching

Not Sanchez, but his dogs will be missed

Then there is this

So many jokes

Alexis, the piano man