Manchester United flop Alexis Sanchez has cost club a staggering £13.2m per goal, £7.3m per assist

Manchester United will breathe a huge sigh of relief after parting ways with Alexis Sanchez.

The Chilean forward has secured a permanent move to Serie A outfit Inter Milan, where he has been playing on loan since the beginning of the 2019-20 campaign.

Sanchez's career flopped remarkably at Old Trafford following his move from Premier League rivals Arsenal in January 2018, when he was involved in a swap deal with Henrikh Mkhitaryan.

But he endured a nightmare time in Manchester, failing to recapture that form that saw him set the Emirates Stadium  alight between 2014 and 2018.

However, it isn't just on the pitch where Sanchez has plagued the Red Devils over the past couple of years.

United's bank balance has been hit hard.

Sanchez's eye-watering demands at United are well-documented, with the 31-year-old earning a staggering basic salary of £350,000-per-week, before an additional net payment of £100,000 a week from a £5million-a-year image rights deal.

When he arrived at United, it was agreed that additional bonuses and employers' national insurance payments could take the potential overall figure to £560,000 a week if Sanchez was successful.

United have also had to pay £5m in agent fees over the course of the contract to the player's representative Fernando Felicevich - which is the equivalent of £21,370 per week.

And finally, former manager Jose Mourinho and United were so desperate to gazump rivals Manchester City at the time to sign Sanchez, that they committed to an astonishing £6.7m signing-on fee.

But after flopping at United, Sanchez opted for a loan spell at Inter at the end of August last year to try to get his career back on track.

However, the Premier League giants have still been picking up £300,000 per week of his wages while the agent fee is still coming into play.

Sportsmail understands United also paid Sanchez a £9m pay-off fee as part of his move to Inter Milan. The club are said to be very satisfied at the outcome considering Sanchez would have earned in the region of £50m under the terms of his contract at Old Trafford that still had nearly two years to run.

Overall, since his move to United in January 2018 - Sanchez has cost the club an astonishing £66,420,840 (taking into account his weekly wages at Old Trafford and Inter - that United were still paying up - during a total of 132 weeks, as well as the agent fees and signing-on fee).

Before his loan spell at Inter, United forked out £34,973,710 overall on Sanchez and since moving on loan to the San Siro, the Red Devils have had to part with another £15,747,130... and that's even before the signing-on fee.

And when you consider that incredible sum and how he has performed on the pitch for United, the figures are absolutely astronomical.

During 89 weeks at United, Sanchez played just 45 times under Mourinho and then Solskjaer - equating to nearly £1.3m per game.

In those 45 appearances, Sanchez has scored a mere five goals, far off from his spectacular numbers in the Premier League with Arsenal where he remained one of the most deadly forwards in Europe.

Therefore, Sanchez has cost United almost £11.5m per goal. He has been far from active in front of the posts, offloading just 22 shots on target in 45 games - matching up to £2.6m for every effort on target.

Assists wise, the former Barcelona star has created nine - which works out at £6.4m each.

And finally, it's in the build-up where Sanchez seemed to enjoy his most success for United, creating 72 chances overall for team-mates.

That equates to £798,000 per chance for the Red Devils during his nightmare time at the club.

So it's fair to say that United were keen to get Sanchez off the books as quickly as possible as they look to make inroads on rivals Liverpool and Manchester City and free up money in order to bring in their desired targets.

Sanchez's departure could save United potentially up to £58m in wages, which would come as a blessing to their manager and the board.

Solskjaer plans on bringing big names in to freshen up his squad and offloading Sanchez makes that easier - England international Jadon Sancho looks set to arrive from Borussia Dortmund.

United are on the verge of agreeing personal terms with the 20-year-old winger on a five-year contract - a deal that could reach an eventual £108m for one of Europe's biggest talents.

After securing Champions League football next season for United, it's time for Solskjaer to firmly look forward without Sanchez.

Meanwhile for Sanchez, his Inter move represents the perfect chance to kickstart a career that has rapidly declined beyond belief in recent times.