Odd Future, Kaiser Chiefs and Jimmy Eat World provide support at Tennent's Vital

August 2011 saw a whole host of musical stars descend on Northern Ireland, but in terms of pulling power, arguably no single day has matched the concluding leg of this year's Tennent's Vital.

After a three year absence the former Belfast-based festival reboots at Ward Park, the Bangor sports ground which last year made Snow Patrol's homecoming the highest attended concert in the country's history.

The opening day has already hosted a headlining performance from Dublin chart-toppers The Script, and more notably, hometown sensations Two Door Cinema Club (watch a video interview below). But for the greater number of Vital attendees Day Two is the preferential draw.

If forced you'd stab a guess that it's because global rap phenomenon Eminem tops the bill in his inaugural Northern Irish appearance, having already conquered the south at Oxegen in 2010.

The remainder of the predominantly hip-hop orientated line-up is a curious, if not broad assembly of names. No doubt intended to cast the net as widely as possible, but inevitably because of the headliner's overbearing shadow and a deadening downpour, the support acts enjoy varying degrees of success throughout the day.

Main stage openers The Knux are a proposition that most are surely unacquainted with. Despite being an unknown quantity, the alt-rap trio – who dabble in everything from rock-scored hip-hop to full pelt drum'n'bass – immediately own the early crowd and turn in one of the day's winning sets.

Brimming with charisma, joyously dumb Kravitz riffery, lightning-juiced beats, and ending with a clever DJ mash-up of 'Jump Around' and 'The Power', The Knux capture the summery hip-hop nostalgia. It's just a shame that most ticket holders who arrive later miss out.

With the throng warmed up, D12 bundle on stage to capitalise. The raucous mob are most famed as the long time group project of Eminem. As veteran performers, therefore, they're immensely fun, even if the mindless and obnoxious gun shot effects truly irk the brain (turns out we're in for a lot more of this as the day wears on).

'My Band' and 'Purple Pills', the decade old hits we'd all but forgotten, are highlights pulled off with all the theatrics their respective videos are known for, and the trash talk between songs, although a little too rehearsed, is as rousing as it is foul-mouthed. It's not the last we hear from the rowdy bunch either, but for now they tick all the boxes for a great festival act.

In theory, as another hip-hop horde, OFWGKTM (or Odd Future) could be foreseen as an act similar to D12 in theory, but in reality they couldn't be further apart. Led by Tyler, the Creator, they aren't a party band so much as a lawless collective, notorious for shock-tactic lyrics, chaotic performances and being a trendy favourite of the music press.

They're by no means underground anymore, but hardly mainstream in today's setting. They bound on stage amongst a hail of obscenities and cold aggression that no one here can relate to, but as they feed off the indifference things get more interesting.

Tyler enters the fray on a bicycle and, despite an injured leg, is, before long, off stage and amongst the crowd attempting to incite the type of mayhem that's standard fare at their smaller venue shows. When the atmosphere doesn't ignite as they hoped it would, their discontent is plain to see. But instead of trying to connect with the audience they throw tantrums indicative of their youth. Swiftly the masses turn on them and the set is abandoned to a chorus of boos and hostility.

Musically they're more solid than the attitude would suggest, but for a major festival main stage crowd this car crash of temperaments could have been predicted. As a result it feels like Odd Future won't be hurrying back to these shores any time soon.

US pop-punkers Jimmy Eat World are a welcome change of approach, but are dealt an instant blow when the rain starts, muting almost every pocket of enthusiasm amidst a crowd seemingly switched off by the sight of a conventional rock band.

In these parts the Arizonians live off cult status. Admirably, however, they don't let the mild reception stint their professionalism. If nothing else though, it's the happiest sounding relief from the weather.

Mercifully the rain abates, allowing Kaiser Chiefs to dazzle with a greatest hits set of sorts. Frontman Ricky Wilson lives and breathes this kind of setup, conducting Mexican waves and gunning it to the second barrier to acknowledge the fans further back.

Always running the risk of ripping the red carpet right from beneath Eminem's feet, for a support slot it's world class even if not all of the material quite holds up. Thankfully they're sparing with the dismal recent album, and for the most part give us the boozy anthems we came for.

'The Angry Mob' and 'I Predict A Riot' are standard issue fest-fizzers, giving it a good shaking until 'Ruby' and 'Oh My God' blow the cork off the place. It's loutish and not overly intelligent, but in a massive damp field with a foamy pint in hand there's no one we'd rather have.

Finally, after the day's longest changeover, the very reason north Down has been brought to a standstill arrives as Eminem launches into a near two-hour smash hit parade of stadium rap that just falls short of being the extravaganza we hoped it would be.

The smattering of pre-retirement bleach-blonded singles provide the best moments in the first hour. There's the chorus-sampling power ballads ('Sing For The Moment', 'Like Toy Soldiers'), spleen-filled tirades ('Cleanin' Out My Closet', 'The Way I Am') and of course, the cinematic anthem 'Stan', complete with a competent though anonymous guest vocal – not that anyone was expecting Dido.

Aside from such songs, however, Eminem is over-reliant on his comparatively pedestrian comeback material, and the lukewarm welcome to almost everything released since his re-emergence speaks all too loudly, all too often.

While it's probably best there's no room for repugnant skits like 'Just Lose It' or 'Ass Like That', it's the absolutely monumental medley of 'My Name Is/The Real Slim Shady/Without Me' that tonight will be best remembered for. Suddenly we're transported to a simpler, less world-wise age when Em's lyrical horseplay was the global media's prime concern.

Yet Mathers remains a great showman, and even if no one's bothered to tell him we're not in the capital he succeeds in making this performance feel as personal and involving as it can be, refereeing a 'ladies' versus 'fellas' noise war, name-dropping Belfast in lyrics and instructing for the lighters to be brought out.

Long time fans are disappointed in some glaring omissions and only snippets of the classics competing with fuller versions of new singles, but with so many hits and such widespread appeal a perfect setlist would be an impossibility. It's a welcome return for Tennent's Vital, and, despite being stereotyped as drunken gingers and branded mofos on countless occasions, we'd all welcome Em back next year.