It looked like Manchester United's woeful run was primed to continue on Tuesday as Michael Carrick's faltering side fell 2-0 down inside the first 20 minutes of their UEFA Champions League tie against AS Roma, much to the audible dismay of the Old Trafford crowd.

With the home team offering little in the way of attacking impetus and repeated defensive errors leaving the back line vulnerable, the atmosphere inside the stadium was largely despondent. Indeed, with their team already two goals behind, disgruntled fans took it upon themselves to stage a planned protest in the first half as dozens of tennis balls were hurled from the stands onto the pitch to disrupt the game.

Play was halted for several minutes while the balls were cleared, allowing United to limp onto the half-time break. The interval then seemed to ignite a fire under Carrick's beleaguered side, who staged an exhilarating second-half comeback to win the game 3-2.

While it's unlikely the tennis ball protest made as much impact on proceedings as the half-time barracking delivered by Carrick and his staff, it certainly raised awareness of the discontent mounting among the supporter base.

While chants and banners in the terraces are a fairly commonplace way for soccer fans to voice their discontent, sometimes they step it up a notch. Here's a look at some of the various approaches adopted by supporters to really get the message across.

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Foreign objects

United's tennis ball protest during the Roma game certainly wasn't the first of its kind, with Celtic supporters orchestrating a much more effective demonstration last year by hurling balls onto the pitch during a Europa League game against Stuttgart.

Borussia Dortmund's famous "Yellow Wall" also brought a 2024 Bundesliga match against SC Freiburg to a halt by throwing balls and chocolate coins onto the pitch in protest of an unpopular media investment proposal being floated by the German football association.

Perhaps the most unusual pitch pelting on record came during the 2016 League One game between Charlton Athletic and Coventry City in 2016 when both sets of fans decided to protest against their respective owners by lobbing hundreds of little pink, plastic pigs out onto the turf.

Plane banners

A tried-and-true method of getting your message seen, several fan groups have organized banners to be flown over their stadiums on match day in order to broadcast their grievances to the wider world. Indeed, Manchester United fans have rallied against their owners in the skies above Old Trafford in the past -- notably after reaching the end of their tether with David Moyes' managerial tenure.

After failing to convince supporters of his "Chosen One" credentials after replacing Sir Alex Ferguson at the United helm, a banner reading "Wrong One - Moyes Out" was trawled over the stadium during a game in March 2014. Sure enough, Moyes was promptly relieved of his duties the following month.

Alternate colors

With so much to grumble about on a weekly basis, another notable Manchester United fan protest strategy is the wearing of the club's original colors which were sported by the team during their formative years as Newton Heath at the turn of the 20th century.

When times get really trying at Old Trafford, an increasing number of green and gold shirts and scarves (and even balloons) can be seen dotted around the stands -- a clear and concise signifier of the general distaste at the way in which the club is being run in the modern era. Even former United midfielder David Beckham donned one after playing at Old Trafford with AC Milan in 2010.

White handkerchiefs

Co-opting a practice from the world of bullfighting, Real Madrid fans traditionally show their dissatisfaction at the Bernabéu by waving white handkerchiefs in the stands.

The protest is known as a "pañolada" and is used to signal disapproval and an unwillingness to accept mediocrity -- the most recent example coming in January of this year when the Madridistas chose to jeer their side during a match against Levante after losing back-to-back games against rivals Barcelona in the Spanish Supercopa and second-tier Albacete in the Copa del Rey.

Fan marches and rallies

Many fan groups have banded together to protest against their clubs by staging marches along the street. Usually organized as a show of objection against a maligned ownership regime, the marches consist of supporters gathering to carry their message to the stadium on matchday, where the protests can continue on the concourse outside.

Last season Liverpool supporters gathered in droves outside Old Trafford to protest rising ticket prices, warning that the soul of their Anfield stadium could be at risk should the club continue to price fans out.

This wasn't the first time that Reds fans gathered to show their disapproval at the club hierarchy either, with thousands massing in Liverpool city center and outside Anfield at various points to rally against the ownership of U.S. businessmen Tom Hicks and George Gillett Jr., who eventually sold the club to Fenway Sports Group in 2010.

Hitting the post

For a year or two, football witnessed a spate of games being disrupted by people attaching things (including themselves) to goalposts in order to stage a mid-match protest. For example, at Goodison Park in 2022 a young climate-change activist brought the Premier League game between Everton and Newcastle to a halt by running onto the pitch and tying himself to the goalpost. Match stewards managed to carefully free the protestor using a pair of wirecutters but not before the game was postponed for around 10 minutes.

One of the most memorable incidents that was the direct result of fan action came in Germany two years ago when a second-tier game between Hamburg and Hannover had to be paused after a supporter leapt over the barricades and affixed a heavyweight metal bike lock to the goalpost in protest over the league's plans to attract private investment. The game was actually repeatedly besieged by protests, but the most disruptive proved to be the lock, which took a steward wielding a power saw to remove.

Empty seats

With the elite level of the professional game becoming increasingly expensive and inaccessible, many fan and supporters' groups have taken action to pointedly demonstrate their opposition using boycotts, walk-outs and sit-ins.

For example, Bayern Munich fans once staged a punchy protest against the high price of match tickets for a 2017 UEFA Champions League group game at the Emirates by refusing to take their seats for the first five minutes of the game, leaving the away section eerily empty for the duration.

In a show of solidarity, the Arsenal supporters then vociferously applauded the Bayern fans as they belatedly filtered into their seats and unfurled one banner reading "without fans, football is not worth a penny."

One of the most memorable examples of a mass-walkout came in 2016 when around 10,000 Liverpool supporters upped and left their seats over the spiraling cost of season tickets in what was Anfield's first ever organized walkout.