Local media have reported that the exciting Spanish international could become the Barcelona squad's highest-paid player if he meets certain performance-related clauses.
The veteran Polish forward, 36, reached 27 league goals for the season, although he finished behind Real Madrid's Kylian Mbappe on 31.
The win comes against a mighty Barcelona team considered on paper to be the best in the world.
The Brazilian, whose previous deal was set to expire in 2027, was vital as Barcelona won a domestic treble of La Liga, the Copa del Rey and the Spanish Super Cup.
Villarreal qualified for next season's Champions League with an entertaining 3-2 win at newly-crowned La Liga champions Barcelona on Sunday.
Barcelona's 28th Spanish league title caps a remarkable season defined by teenage sensation Lamine Yamal, who at 17 has emerged as world football's most electrifying talent.
A stunning Lamine Yamal strike helped crown Barcelona LaLiga champions with a 2-0 win at local rivals Espanyol on Thursday, with victory ensuring Real Madrid cannot catch them at the top of the table.
Defending champions Real Madrid may well lose the LaLiga title race to archrivals Barcelona tonight, but Los Blancos were happy to keep the fight alive for another day with a last-gasp 2-1 home win over Mallorca on Wednesday.
Real Madrid snatched a last-gasp 2-1 win over Real Mallorca on Wednesday to delay Barcelona's title celebrations.
Inter Milan coach Simone Inzaghi lavished praise on Barcelona's teenage winger Lamine Yamal after a thrilling 3-3 Champions League semi-final first leg draw on Wednesday.
Barcelona and Inter Milan shared a compelling 3-3 draw in a high-octane Champions League semi-final first leg clash on Wednesday.
Barcelona twice battled back to draw 3-3 at home against Inter Milan in a rip-roaring first leg of their Champions League semi-final at Montjuic Olympic Stadium on Wednesday.
Lamine Yamal and Ferran Torres levelled for Barcelona in the first half after two early Inter strikes.
Now the Catalan giants rely on another generational talent in Lamine Yamal as their 'X-factor' when they host Inter Milan on Wednesday in a semi-final first leg clash.
Inter Milan coach Simone Inzaghi said he and his team respect Barcelona but are not afraid of them, ahead of their Champions League semifinal duel on Wednesday.
Barcelona star Lamine Yamal said he is focussed on being himself and not on comparisons to Lionel Messi, ahead of the Champions League semi-final clash against Inter Milan on Wednesday.
In a breathtaking Copa del Rey final at La Cartuja, Jules Kounde’s 116th-minute rocket sealed Barcelona’s thrilling 3-2 win over Real Madrid.
French defender Kounde struck in extra-time to settle a wild Clasico in Barcelona's favour, with the Catalans triumphing 3-2 in Seville.
The Catalans, aiming for a quadruple this season, won the first major trophy of Hansi Flick's reign as coach and a record-extending 32nd Spanish cup in dramatic fashion
