Twenty-five years ago, when quizzed about the differences between club football and international football, legendary Italian coach Arrigo Sacchi had one simple conclusion.

"Football should always be played at the highest possible level," he declared, "and no club will ever reach the level as an international side."

That was conventional wisdom back then: International tournaments were considered the pinnacle of football, with clubs playing something of a feeder role.

In recent years, however, it's become impossible to genuinely believe that international football is a step above club football, for a variety of reasons -- and this summer's World Cup may underline that point more than ever.

The most significant development in the shift of power from international sides to clubs was the Bosman ruling in 1995, which effectively meant neither domestic leagues nor UEFA were able to enforce three-foreigner laws in their competitions. They could maintain similar rules for non-EU players, but teams from EU countries could, for the first time, field as many "foreign" EU nationals as they wished.

This completely changed the situation for Europe's top clubs. Previously their starting XIs were generally comprised of (at least) eight players from their country, with a trio of exciting foreign players to "top-up" their quality. Suddenly, it was entirely possible to field a team of 11 foreigners -- and it took just four years after the Bosman Ruling for Chelsea to do precisely that, in late 1999. Top clubs could assemble talents from across the continent, and were free to construct sides far better than national squads could imagine.

A subsequent development was the increased level of financial inequality within top leagues, fueled by Champions League revenue, increasingly sophisticated marketing and, in some countries, scandalously unequal distribution of domestic television revenue. Consequently, the top clubs became even more dominant, often assembling second-string XIs that were superior to mid-table sides in the same division. Again, it inevitably boosted the level of the top club sides beyond what international sides could assemble.

Another crucial factor is the increased level of tactical sophistication at club level. Strategic plans are now incredibly complex in terms of positioning, passing patterns and pressing triggers, and international managers frequently complain they simply don't have enough time to replicate those training sessions. That's always been the case, of course, but it's become particularly apparent over the past decade or so, in an era in which managers are now considered primarily in tactical terms rather than, for example, as man managers or talent spotters.

But the reason this year's World Cup might feel particularly flat, at least in the early stages, is the obsession with pressing among top club managers over the past few years. Pressing is not a new concept, of course, but its popularity has grown considerably over the past few decades, morphing from a useful "bonus" concept that proved a side was organised and hard-working, to often being considered a side's main tactical plan. Mauricio Pochettino's Tottenham, for example, were a great pressing side before they offered a particularly strong identity in possession. Jurgen Klopp's Liverpool implemented good counterattacking before good counterpressing.

Don't expect to see much Liverpool-esque high-pressing football at the World Cup this summer. Getty

The rise of pressing has been so spectacular, so successful and so popular that it's now widely expected of top sides. Everyone has become so accustomed to such ferocious, high-intensity, 100 mph matches like those involving Liverpool in this season's Champions League, that more sedate, patient matches are considered terrible games, which is somewhat worrying ahead of the World Cup.

Chelsea's 1-0 victory over Manchester United in the FA Cup final, for example, was a perfectly decent match, featuring a good level of technical quality, an outstanding individual performance by Eden Hazard, an interesting tactical battle between two fine managers, tension and intrigue throughout and a good number of chances. It basically had all the ingredients for a good game, especially in the context of finals, which are naturally cagey and conservative. Yet the game was widely panned. The only logical explanation is that people were disappointed by the slow pace, owing to a lack of pressing.

If that match was widely considered unenjoyable, you wonder precisely how much people will actually enjoy the World Cup. Pressing at international level is considerably rarer, in part for aforementioned problems involving a lack of training ground time, but also for fitness reasons. Players are exhausted after a long, hard season, and no one fancies the idea of pressing intensely, for, in theory, seven matches in the space of a month.

Very few teams will press intensely at this summer's World Cup. Spain are a notable exception judging by their performances in qualification, as are Germany. Jorge Sampaoli bases his philosophy around pressing and may do something similar with Argentina, although the manner in which their high line was destroyed by Spain in a 6-1 friendly defeat in March means he may be forced into a rethink. Brazil, England, France and Belgium may press high to force the issue against weaker sides, but equally might fancy their chances of sitting deep and counterattacking against fellow contenders.

The vast majority of teams at this World Cup, however, will take the cautious approach of standing off the opposition and sitting deep in their own half. In some cases, this will result in groups -- A and H in particular -- in which all four sides are content to drop back and wait for the opposition to come to them. This is no different from the situation at previous World Cups, but somewhat out of keeping with the high-tempo, frenetic football we've become accustomed to at club level in recent years.

Combined with the fact that this World Cup isn't particularly blessed with strength in depth -- outside the top six or seven sides, there isn't a great deal of quality -- and the entertainment value of the tournament could be somewhat lacking in the first couple of weeks. In terms of both quality and entertainment value, international football is now way behind club football, which means this summer's matches in Russia -- at least in the group stage -- might feel somewhat underwhelming.