Barcelona's Lionel Messi celebrates scoring against against Osasuna with Dani Alves during their Spanish Kings Cup soccer match at Camp Nou stadium in Barcelona January 4, 2012.??[Photo/Agencies]

MADRID - Lionel Messi and Cesc Fabregas each scored twice as Barcelona thrilled the Nou Camp with a crushing 4-0 win over Osasuna in their King's Cup last-16 first leg on Wednesday.

The Spanish and European champions dominated their La Liga rivals from start to finish and the victory was made all the sweeter when talisman Messi came off the bench to add two goals to first-half strikes from former Arsenal captain Fabregas.

Barca had said earlier on Wednesday Messi would miss the game because of flu and fever but club doctors managed to subdue the illness sufficiently for the Argentine World Player of the Year to replace Pedro for the final half hour.

Barcelona's Cesc Fabregas (L) and Dani Alves celebrate a goal against Osasuna during their Spanish King's Cup soccer match at Camp Nou stadium in Barcelona, January 4, 2012.??[Photo/Agencies]

Fabregas put the home side ahead in the 13th minute and doubled their lead five minutes later with a fine piece of close control and a sublime chip over Osasuna goalkeeper Asier Riesgo.

Messi netted a rare header 20 minutes from time before picking up a Xavi pass on the edge of the area, the Spain's playmaker's third assist of the night, and curling a shot into the corner of the net.

Barring upsets in next week's second legs, Barca will face great rivals Real Madrid in the quarter-finals, who beat them 1-0 in last year's final and came back from two goals down to win their last-16 first leg against Malaga 3-2 on Tuesday.