Nas and Damian Marley perform at the Molson Amphitheatre on July 5, 2009. (Ernest Doroszuk. Sun Media)

TORONTO - This year's version of Rock The Bells came off pretty much without a hitch as rapper Nas and reggae star Damian Marley capped off the day-long affair Sunday before a roughly half-filled Molson Amphitheatre.

The duo, who are working on a forthcoming studio album together entitled Distant Relatives, joined forces on a few songs during their approximately hour-long set but primarily took turns strutting their goods.

And judging by the crowd's response, the goods were quite good early on as Nas took to the stage with Hip Hop Is Dead and The World Is Yours, his rapid rhymes and wordplay far outweighing any bling he was sporting.

Following If I Ruled The World (Imagine That), Nas introduced Marley before delving into a promising new song titled Afro Beat that meshed the hip-hop component quite nicely with Marley's dancehall, groove-riddled sound.

Marley - sporting lengthy dreadlocks that Crystal Gayle might envy - also riled the standing audience up with snippets of his legendary father's hits such as One Love and Exodus when not performing his own tunes such as Welcome To Jamrock and More Justice.

Fortunately the headliner wasn't the only act worth seeing, with Outkast's Big Boi cramming in as many hits from the group's career in 30 minutes as possible. With various videos synched up perfectly to his raps, Big Boi dazzled the crowd with Ms. Jackson, I'm On It (Kryptonite), So Fresh So Clean and especially The Way You Move.

One of the last-minute surprises might have been including Mos Def on the bill after Common - originally slated for the concert - backed out due to a film commitment. But Mos Def made the most of the slot, delivering tunes that rarely fit the traditional hip-hop backbeats. Whether it was Universal Magnetic, Auditorium or teaming up with Talib Kweli for their hit Black Star, the artist did it his way for most of the way.

After a handful of early performers greeted the fans coming in, Wu-Tang Clan's RZA - celebrating the big 4-0 at the concert - kicked things into another gear with 1-800-Suicide before turning into his Bobby Digital character for You Can't Stop Me Now. And like a number of acts throughout the day, RZA paid tribute to the late Michael Jackson.

Perhaps the warmest welcome was for Somalia-cum-Canada hip-hop artist K'Naan. The hometown musician - and one of the few with a support band behind him -- did an a cappella version of Somalia not found on this year's Troubadour album which shone as well as the feel-good, catchy Wavin' Flags and ABCs.

If there was one disappointment, it might have been how high up in the bill '80s rap group EPMD. The duo of Erick Sermon and Parrish Smith had the crowd up for You Gots To Chill and Crossover but seemed to run out of steam early on as did most of the fans who began sitting down.

Thankfully, the biggest bright spot might have been how organized the gig was, with everything running on time and everyone having made it across the border.

SUN RATING: 4 OUT OF 5