Officially, it's called a water feature. On the upper deck of the 22,000-seater Banc of California Stadium, behind the posh seats and ornate tables, a 17-inch deep body of water overlooks the streets of Los Angeles.

Another inch, and it would be classed a swimming pool and require a lifeguard. For now, fans can pay to take a splash unsupervised, as the action unfolds below.

It's less than four years since Los Angeles FC dipped their toes in the US football market. Built from scratch, they began with no players, no stadium and no coach. Only a dream. Now Bob Bradley's side top the Western Conference.

Wayne Rooney may be set to depart MLS but football in America is a growing entity

Los Angeles FC fans can take a splash in an incredible 17-inch deep pool inside their stadium

Since their first MLS match in March 2018, they have come to embody a sport that has barged its way into the American national consciousness.

Wayne Rooney may be about to quit MLS but he is not fleeing a sinking ship. Rather, the sport here is booming. Crowds are growing, the standard is improving and the money involved is rocketing.

Now, 23 years after the founding of Major League Soccer, football is the joint-second most popular sport among Americans under-35s. It has spread its wings to Canada, too, and soon six more teams will join the party.

Sunday's clash between LAFC and LA Galaxy, and the derby between Portland Timbers and Seattle Sounders on Saturday, were further evidence of why MLS's dreams of becoming a major player are anything but far-fetched.

Zlatan Ibrahimovic bagged his seventh and eighth goals against LAFC for LA Galaxy on Sunday

And yet why there is still much to do.

One hundred and six seconds. Galaxy star Zlatan Ibrahimovic doesn't get paid for overtime and on Sunday he wasted little time bursting the LAFC bubble.

Football in America has long battled to shed its skin, to move beyond the mockery and become more than a holiday destination for ageing stars looking to make an easy buck. Yet Zlatan is 37 and scores for fun. He was statuesque during the match on Sunday, and not just when he celebrated.

But few clubs illustrate the progress made more obviously than LAFC. The team are a triumph in market research. Thanks to a fierce political-style grassroots campaign, they have captured the imagination of the Los Angeles public, particularly its Hispanic population. So much so that they're already outgrowing this £286million ground.

The atmosphere had a strong Latin American flavour as the crowd sang and bounced for 90 minutes, their vision hampered by flares and luchador masks.

And the presence of Hollywood celebrities, including Natalie Portman and Kevin Costner, showed how football is breaking through in a city and a country rich with sporting competition.

The atmosphere had a strong Latin American flavour as the crowd sang for 90 minutes

Yet within 15 minutes, Ibrahmovic had scored his seventh and eighth goals in five El Trafico meetings.

Twice the Swedish striker took advantage of shoddy defending. Twice he stretched out his arms in front of the North End.

It was a powerful image. MLS hopes to surpass the country's traditional sporting institutions of baseball, basketball, hockey and American football, and the league have targeted a different demographic — diverse, urban, young and loud.

Nowhere is that seen more clearly than in the North End, which holds the LAFC hardcore supporters. Against a backdrop of black and gold, flags from Brazil, Mexico, and El Salvador wave alongside the Stars and Stripes. And on the hour, it was their darling, former Arsenal striker Carlos Vela, who scored the equaliser in a 3-3 draw.

Former Arsenal striker Carlos Vela had netted the equaliser in the six-goal thriller

The thunderous atmosphere had bubbled since mid-morning and didn't relent until full-time.

The crowds here are far more inclusive, with women leading the chants in the North End, where the rainbow flag flew proudly. But the carnival does occasionally stop.

Two days earlier, Portland and Seattle made a rather quieter statement. For more than half an hour, a hush hung over Providence Park like dense fog as one of America's fiercest derbies morphed into a silent protest.

Supported by their clubs, fans were fighting for their right to display an anti-fascist symbol. MLS have banned political signage, so supporters decided: if they want to keep us quiet, let them see how silence feels.

The two fan groups, divided by years of bad blood, came together to make a stand during a game against their biggest rivals. The affair won't feature in many MLS marketing booklets, but it was a powerful demonstration of football culture in the US. This week's north London derby is unlikely to feature such solidarity.

Portland and Seattle's protest was a wider illustration of how much this sport matters now. Just ask Timber Joey, the lumberjack team mascot who for more than a decade has stood pitchside with his chainsaw, cutting a giant log to mark every goal and clean sheet.

Portland mascot Timber Joey is now part of the fabric in one of the US' proudest football towns

He was on his way to the UK to play rugby when injury curtailed his career. Now he's part of the fabric in one of America's proudest football towns. They call Portland 'Soccer City USA', but increasingly, in LA and other corners of this vast nation, supporters are engaged, the league is taken seriously, and football can be a vehicle for difference.

Among the victorious Sounders squad was Brad Smith, formerly of Liverpool and on loan from Bournemouth. Eddie Howe was apparently shocked when told the defender was considering a move across the Atlantic. But Smith, 25, has swapped the 11,000-capacity Vitality for Seattle's 72,000-seater CenturyLink Field. Step down? It doesn't feel like it.

Smith claims a number of players have contacted him about making the same step. But while they await the arrival of more players from Europe, clubs in MLS have to be inventive. Unable to compete with the worldwide powerhouses, they have turned to the South American market.

Bournemouth manager Eddie Howe was shocked when told Brad Smith would move to MLS

Many clubs lack the quality and depth of their counterparts elsewhere, but smart transfer business has improved the standard and made this the most diverse league in the world.

Mexico's Vela is proof that players can make their reputation in Major League Soccer, not just risk tarnishing them. He shared the spoils with Ibrahimovic, who aside from his goals, virtually stood still for 90 minutes.

Nevertheless the sport in America is changing around him — and only heading one way.

LAFC may still live in the shadow of the LA Rams, whose temporary home, the 77,000-seater Coliseum, stands next door in a fitting illustration of how the NFL still dwarfs its rivals. But with every water feature and every passing year, football edges closer to victory in battles at home and abroad.

In the North End, in Portland, and elsewhere, football in America is making noise. Even when its fans stay silent.