Xavi has said Barcelona must continue to improve and has urged the club to sign new players this summer to close the gap on rivals Real Madrid.
Restricted by major financial problems, Barcelona endured a turbulent and trophyless season that saw former manager Ronald Koeman sacked in November and replaced by club legend Xavi.
Bolstered by the January arrivals of Pierre-Emerick Aubameyang, Dani Alves, and Ferran Torres, the former Barca midfielder orchestrated an impressive turnaround to guide the club to second in La Liga. But they still finished 13 points behind champions Real Madrid, ending the campaign with a 2-0 home defeat by Villarreal, and were eliminated from the Europa League quarter-finals by eventual winners Eintracht Frankfurt.
Barca were on a plane the morning after the loss to Villarreal for their first-ever match in Australia, a friendly against an A-League All-Star team coached by former Manchester United striker Dwight Yorke and captained by former Manchester City midfielder Jack Rodwell.
Xavi has taken 20 players to Sydney, including captain Sergio Busquets, Dani Alves, Aubameyang, Frenkie de Jong, Memphis Depay and teenage sensation Ansu Fati. Gerard Pique and teenage forward Pedri were among those missing.
"Next season we need to improve a lot, we improved a lot since November," said Xavi, who was appointed with Barcelona lying ninth in La Liga and on the verge of getting knocked out of the Champion League group stage.
"I think we are in a good way, we have to be positive. But next season, at least, we need to compete and win the Champions League, why not?
"We are rebuilding the team. We have a plan, of course, and we need to be competitive next season. We cannot permit another season without winning titles."
Prolific Bayern Munich forward Lewandowski, who was top-scorer in the Bundesliga last season for the fifth year running, has been heavily linked with Barcelona.
His agent, Pini Zahavi, told German daily Bild this week the striker wants to leave Bayern, with Barcelona reportedly offering €32 million to sign the 33-year-old Pole.
Xavi, however, refused to be drawn into the speculation.
"I cannot confirm Lewandowski or any other names," he said. "Of course we are working hard and it is obvious that we need to improve.
"It's a matter of time [that Barcelona will sign new players]. If we have to announce something we will announce it, but it is not the moment right now."
