On the face of it, Wednesday was a bad day for Jose Mourinho. Manchester City stretched their lead at the top of the Premier League to 15 points and Liverpool made Virgil van Dijk the world's most expensive defender by striking a £75 million deal with Southampton for the Netherlands centre-back.

Just 24 hours after insisting that Manchester United could only close the gap on Pep Guardiola's league leaders by spending more money, Mourinho must have felt that he was being hit from both sides with City coasting to victory at Newcastle and Liverpool's American owners sanctioning the huge move for Van Dijk.

But the flip side for Mourinho is that the events of Wednesday evening offered him the ammunition, if needed, to strong-arm United executive vice-chairman Ed Woodward, and the Glazer family, United's owners, into coming up with the funds he believes are required to make his team contenders rather than merely the best of the rest.

There was little immediate support for Mourinho in the wake of his comments, following Tuesday's 2-2 Old Trafford draw against Burnley, which suggested that, despite spending more than £300m on new players since arriving at United 18 months ago, the team still needed much more investment in order to compete with City.

But the reality is that, regardless of the vast sums spent by Mourinho at United, they are still in need of at least four players to take them to the level at which both they and the manager expect to be.

United under Mourinho are a paradox, so his comments cannot be dismissed out of hand as little more than sour grapes after spending a fortune.

The money spent has triggered a big improvement at United under Mourinho -- they won two major trophies in his first season last year and they currently sit second in the Premier League with 10 more points than at the same stage of last season.

Jose Mourinho wants Manchester United's to spend more despite paying big fees for Romelu Lukaku and Paul Pogba. Getty

After drifting for three years under David Moyes and then Louis van Gaal following Sir Alex Ferguson's retirement in 2013, when fourth was the best finish United achieved, Mourinho has made United strong again and taken them back above the likes of Liverpool, Arsenal, Tottenham Hotspur and Chelsea.

The only problem for Mourinho and United is that City have pulled away from them and everybody else, disappearing over the horizon at a rate of knots.

As a result, United's improvement under Mourinho has been distorted by the performances of the team three miles across Manchester at the Etihad Stadium.

So while United's big spending on the likes of Paul Pogba and Romelu Lukaku has worked to a certain extent, in taking them above the pack, it has not come close to landing a blow on City.

There are many reasons for United's failure to compete with City and the spending gap over the last 18 months is only one of them.

Guardiola has signed 16 players as City manager, with Mourinho recruiting seven for United.

In terms of basic figures, Guardiola has outspent Mourinho by £75m in his time at the Etihad, but that figure leaps to £110m if add-ons and incentives are included.

Either way, City have invested more in their squad, both financially and in terms of personnel, since Guardiola arrived than United have under Mourinho.

And Guardiola was working with stronger foundations when he walked into the Etihad than those Mourinho inherited at Old Trafford.

Pep Guardiola inherited a better squad than Jose Mourinho and has had more transfer funds to work with. John Peters/Man Utd via Getty Images

City's squad was a strong one that was under-performing. United's was a collection of good, bad and indifferent signings which had been drained of confidence and belief by Moyes and Van Gaal.

Mourinho had more work to do with the United squad than Guardiola at City and the £300m was needed -- but he clearly needs to spend more, not to be better than the rest, but to compete with City.

Only time will tell whether that money will be forthcoming, but with United needing two new full-backs, at least one midfielder, a left winger and a No. 10 in the mould of Eden Hazard or Philippe Coutinho, Woodward and the Glazers will not get much change out of £200m.

But United's owners are now discovering the full cost of their spending policy during the final years of Ferguson when, following the £80m world-record sale of Cristiano Ronaldo to Real Madrid in 2009, they sought 'value' signings rather than the stellar deals being done by City for the likes of Yaya Toure, David Silva and Sergio Aguero.

A combination of arrogance, complacency and stubbornness saw United stand aside while City invested in both the present and the future.

The failure to keep step with City in the transfer market in the early years of this decade is why United have spent the post-Ferguson years spending, and wasting, money in a misguided attempt to close the gap. It is why £300m has not been enough for Mourinho to make them title challengers.

The former Chelsea manager has made it clear what he and the team needs to do that. So what happens next will tell us whether United still have the ambition to be the best or if being the best of the rest is enough.