It was a day for the youngsters, with Riqui Puig, Ansu Fati and, to a lesser extent, Ronald Araujo all staking their claim to be involved against Napoli. Puig shimmered in midfield, creating two goals, while Ansu scored his eighth goal of the campaign. With Gerard Pique suspended and Samuel Umtiti injured, Araujo ended the game as Barca's only centre-back when Clement Lenglet went off injured.
Elsewhere, Messi's brace should see him wrap up the Pichichi Trophy -- the award for La Liga's top scorer -- for the seventh time in his career and the fourth season running. He has 25 goals, four clear of Real Madrid's Karim Benzema, who has one game to play.
With Napoli around the corner and Barca's squad dangerously short -- they had just three outfield substitutes against Alaves -- the Catalans will desperately hope Lenglet was only taken off as a precaution.
Manager rating out of 10
7 -- Quique Setien couldn't do much given the lack of players available due to injuries and suspensions, but he got it right by starting Puig and Ansu and this was a more lively Barca performance. They hit the woodwork three times before opening the scoring and could have scored way more than five.
Player ratings (1-10; 10 = best, players introduced after 70 minutes get no rating)GK Neto, 6 -- Made just his second appearance in the league this season and his first since January. A relatively easy day's work.
DF Sergi Roberto, 7 -- Started at right-back before finishing the game in midfield. Won the ball back a lot and kept it simple.
DF Ronald Araujo, 7 -- Another decent 90 minutes as the young Uruguayan continues his adaption to the first team.
DF Clement Lenglet, 6 -- Struggled with a knock in the first half and was eventually taken off in the 50th minute.
DF Jordi Alba, 7 -- Set up goals for Suarez and Messi but was sloppy in possession at times.
MF Sergio Busquets, 6 -- Sat deep in the first half, almost becoming part of a back three as he picked the ball up from Neto to start Barca's attacks.
MF Arturo Vidal, 7 -- Hit the bar with a rasping effort in the first half before playing the second half as an emergency centre-back after Lenglet's injury.
MF Riqui Puig, 8 -- Pushing really hard for a start against Napoli in the Champions League. Hit the bar, set up two of the goals and ticked all the boxes required for a Barcelona midfielder.
FW Lionel Messi, 8 -- Hit the post before setting up the opener for Ansu. Then scored two of his own to end the league campaign with 21 assists and 25 goals.
FW Luis Suarez, 6 -- Missed a great chance when sent clear through by Puig but made amends later when he headed in Alba's first-time cross.
FW Ansu Fati, 7 -- Alert in the box to open the scoring and dangerous on the left when running with the ball. What a season he's had.
DF Nelson Semedo, 7 -- Scored his first goal of the season with a well-taken strike from inside the box just seven minutes after coming on.
MF Frenkie de Jong, 6 -- Continued his return from a calf injury with a solid 30-minute showing.
FW Martin Braithwaite, N/R -- Given the final 15 minutes in place of Ansu.