The Brazil international struck after 70 and 86 minutes to break the visitors' stubborn resistance at the Nou Camp on Saturday, easing his team further ahead of their arch-rivals, who travel to Alaves on Sunday.
Substitute Antoine Griezmann's late winner ensured Atletico Madrid remain hot on the heels of the top three after a 2-1 home victory over Valencia.
Skipper Koke had given the hosts a 17th-minute lead, but Diego Simeone's men needed Griezmann's 74th-minute intervention after substitute Lucas Beltran had levelled.
Struggling Real Mallorca eased to a 3-1 win over Elche, while skipper Leandro Cabrera headed Espanyol to a 1-0 victory at Getafe.
Desire Doue's strike proved decisive as Paris St Germain held off Metz at the Stade-Symphorien to move back to the lop of France's Ligue 1 after a 3-2 win.
Goncalo Ramos and Quentin Ndjantou looked to have put PSG in control before Jessy Deminguet reduced the deficit.
Doue re-established the visitors' two-goal cushion and although Giorgi Tsitaishvili pulled another goal back, they saw out the closing stages to move two points clear of Lens, who play Nice on Sunday.
Esteban Lepaul and Mousa Tamari scored within a minute of each other as Rennes came from behind to beat Brest 3-1 and Yann Gboho struck twice in Toulouse's 3-0 win at Paris FC.
Substitute Martin Terrier and skipper Robert Andrich maintained Bayer Leverkusen's distant pursuit of runaway Bundesliga leaders Bayern Munich with a 2-0 win over Koln.
Hoffenheim eased to a 4-1 home victory over Hamburg while Ritsu Doan fired Eintracht Frankfurt to a 1-0 home win over Augsburg.
Patrick Wimmer scored twice in Wolfsburg's 3-1 victory at Borussia Monchengladbach and Martijn Kaars' double secured a 2-1 win for St Pauli over Heidenheim in the battle of the basement boys.
In Serie A, substitute Tijjani Noslin fired nine-man Lazio to a miraculous 1-0 victory at Parma.
The visitors had Mattia Zaccagni sent off three minutes before the break and Toma Basic with 13 minutes remaining, but escaped with the points when Noslin struck eight minutes from time.
Nikola Vlasic's first-half strike was enough to hand struggling Torino a 1-0 home victory over Cremonese, their first in seven attempts in the league, while Gianluca Scamacca's double steered Atalanta to a 2-1 win against Cagliari.
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