Robert Plant, Alison Krauss, Sugarland and Brad Paisley are country's biggest winners at the 51st Annual Grammy Awards.

Plant and Krauss lead the pack with five wins: Album of the Year and Best Contemporary Folk/Americana Album of the Year for 'Raising Sand,' Best Country Collaboration for 'Killing the Blues,' Best Pop Collaboration for 'Rich Woman' and Record of the Year for 'Please Read the Letter.' That's five wins out of five nominations for the duo, who are already hard at work on their second album of duets.

"We are thrilled and very grateful," said Krauss upon accepting the night's biggest honor, Album of the Year. "We'd like to thank the band who played so beautifully on this record ... and special thanks to Robert."

"I'd like to thank Alison Krauss for her kindness, patience and teaching me to sing in straight lines instead of all that swirly stuff," said a beaming Plant.

Krauss and Plant's five out of five sweep is the first since the Dixie Chicks won all five of their Grammy nominations in 2006.

Sugarland are the Grammy winners for Best Country Performance by a Duo or Group for 'Stay,' while lead singer Jennifer Nettles also wins Best Country Song for the hit, which she wrote solo. The duo performed 'Stay' on the live broadcast in a spine-tingling performance, followed by a collaboration with Best New Artist winner, Adele, on her hit song, 'Chasing Pavements.'

Brad Paisley is the Grammy winner for Best Country Male Vocal Performance for 'Letter to Me.' He also won Best Country Instrumental Performance for 'Cluster Pluck,' with James Burton, Vince Gill, John Jorgenson, Albert Lee and Brent Mason.

Carrie Underwood takes home Best Country Female Vocal Performance for 'Last Name,' which she sang on the broadcast in an electrifying performance. George Strait is the winner of Country Album of the Year for 'Troubadour.' Read the full list of winners here.

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Grammy Nominees - Country Categories (*Winners in bold.)

Best Country Album

'That Lonesome Song' - Jamey Johnson
'Sleepless Nights' - Patty Loveless
*'Troubadour' - George Strait
'Around the Bend' - Randy Travis
'Heaven, Heartache And The Power Of Love' - Trisha Yearwood

Best Country Song
(award goes to songwriters)

'Dig Two Graves' - Ashley Gorley & Bob Regan (recorded by Randy Travis)
'I Saw God Today' - Rodney Clawson, Monty Criswell & Wade Kirby (recorded by George Strait)
'In Color' - Jamey Johnson, Lee Thomas Miller & James Otto (recorded by Jamey Johnson)
*'Stay' - Jennifer Nettles (recorded by Sugarland)
'You're Gonna Miss This' - Ashley Gorley & Lee Thomas Miller (recorded by Trace Adkins)

Best Country Performance by a Duo or Group

Brooks and Dunn - 'God Must Be Busy'
Lady Antebellum - 'Love Don't Live Here'
Rascal Flatts - 'Every Day'
Steel Drivers - 'Blue Side of the Mountain'
*Sugarland - 'Stay'

Best Country Collaboration With Vocals

Kenny Chesney & George Strait - 'Shiftwork'
*Robert Plant & Alison Krauss - 'Killing the Blues'
George Strait & Patty Loveless - 'House of Cash'
Sugarland, Jake Owen & Little Big Town - 'Life in a Northern Town'
Trisha Yearwood & Keith Urban - 'Let the Wind Chase You'

Best Female Country Vocal Performance

Martina McBride - 'For These Times'
LeAnn Rimes - 'What I Cannot Change'
*Carrie Underwood - 'Last Name'
Lee Ann Womack - 'Last Call'
Trisha Yearwood - 'This Is Me You're Talking To'

Best Male Country Vocal Performance

Trace Adkins - 'You're Gonna Miss This'
Jamey Johnson - 'In Color'
James Otto - 'Just Got Started Lovin' You'
*Brad Paisley - 'Letter to Me'
George Strait - 'Troubadour'

Best Country Instrumental Performance

Cherryholmes - 'Sumatra'
Jerry Douglas & Lloyd Green - 'Two Small Cars In Rome'
Béla Fleck & The Flecktones - 'Sleigh Ride'
Charlie Haden, Pat Metheny, Jerry Douglas & Bruce Hornsby - 'Is This America?'
*Brad Paisley, James Burton, Vince Gill, John Jorgenson, Albert Lee, Brent Mason, Redd Volkaert & Steve Wariner - 'Cluster Pluck'