Jurgen Klopp and his Liverpool squad were in attendance at the Nou Camp, as Arda Turan scored a hat-trick in Barcelona's 4-0 victory against Borussia Monchengladbach.
Turkey forward Turan also set up Lionel Messi for the first goal of the dead rubber Champions League match.
He then scored a 17-minute second-half hat-trick, as Barcelona underscored their position as Group C winners.
Manchester City finished second, after their 1-1 draw against Celtic.
Borussia Monchengladbach qualified for the Europa League in third despite the loss.
Klopp's Liverpool squad, third in the Premier League after Sunday's dramatic 4-3 defeat at Bournemouth, were on a group-bonding trip.