The Mali striker played winger Jesus Navas through on the right in the ninth minute and surged into the penalty area to pick up the Spain international's low cross and smash the ball into the roof of the net.
Sevilla moved two points clear of Valencia, who were beaten 3-2 by visiting Real Madrid on Saturday thanks to a double from Real's Argentina striker Gonzalo Higuain.
Barca, who have played one more game than all their rivals, have 39 points from 15 matches, five ahead of Real. Sevilla are four points further back on 30 and Valencia have 28.
Earlier on Sunday, Joseba Llorente bundled home the winner in added time as Villarreal battled from a goal down to beat Atletico Madrid at the Calderon.
Both sides had picked up form in recent weeks after poor starts to the campaign and Atletico, going for a third straight win, took the lead through Simao Sabrosa in the 37th minute.
Villarreal began the second period brightly and some woeful Atletico defending gifted them a deserved equaliser on 49 minutes. Joan Capdevila swept over a hanging cross and David Fuster stole in to nod past Sergio Asenjo.
Valverde's side climbed to 10th and Atletico remain in 14th with just 13 points from their 14 matches. In other games on Sunday, Deportivo Coruna were held to a 1-1 draw at struggling Almeria and slipped below in-form Real Mallorca into sixth.
Juan Albin netted twice as Getafe beat promoted Tenerife 2-1, Racing Santander overcame fellow strugglers Xerez 3-2 Real Valladolid drew 1-1 with second-from-bottom Malaga.
Inter held at Atalanta
Serie A leaders Inter Milan were held to a 1-1 draw at Atalanta but AC Milan failed to capitalise when they were humbled 2-0 at home by Palermo on Sunday.
Second-placed Milan slipped five points behind Inter when forward Fabrizio Miccoli scored one goal and helped set up Mark Bresciano for the second in mid-table Palermo's deserved win. Nicola Amoruso missed a penalty but redeemed himself with an 86th-minute winner as fourth-placed Parma came back to win 2-1 at home to Bologna and move two points behind third-placed Juventus, who lost 3-1 at Bari on Saturday.
Sampdoria and AS Roma both edged up to joint fifth after drawing 0-0 in an entertaining late game.
Genoa are among five clubs a point further back after losing 1-0 at Lazio, who recorded only their third league win of the campaign thanks to wingback Aleksandar Kolarov's classy goal. Catania dropped to bottom in Sinisa Mihajlovic's first game in charge after a 1-0 home defeat by Livorno and Siena's 2-1 victory over Udinese.
