Barcelona's players believe Manchester United have improved since the departure of Cristiano Ronaldo to Real Madrid in 2009.

The Portuguese played his last game for United in the European Cup final in Rome – which Barca won 2-0 – before he sealed an £80m move to the Bernabéu.

United ended up with only the Carling Cup in the first campaign following Ronaldo's exit, but this season has seen Sir Alex Ferguson's side reclaim the Premier League title and again progress to the European Cup final, to face Barça on Saturday at Wembley.

"Their team isn't as direct as before; they like to have the ball," the Barça midfielder Xavi said. "I don't know if that's because of Cristiano Ronaldo or not, but they move around as a unit now."

David Villa added: "Cristiano Ronaldo's departure has liberated them. Many great players come and go and that has allowed them to remain at the top for so long."

Dani Alves, the right wing-back, reckons United's threat is harder to nullify in the absence of the Portuguese. "This Manchester United team is much more unpredictable without Cristiano Ronaldo," he claimed. "They have formed a more balanced group and they are stronger than they were two years ago."

Andrés Iniesta also believes United have improved. "They have grown as a team," said the midfielder. "They are dominating in England and now they are fighting for the Champions League. Cristiano Ronaldo has left, but apart from that I don't think they have made big changes and they are always competitive."

Pep Guardiola, Barcelona's coach, sees little difference to the side Barça beat in Rome. "It's the same team. Only one player is missing from the team that started in Rome," he said. "Only Cristiano Ronaldo has left from that team. [Carlos] Tévez isn't there any more either, but he didn't start [the game]."

The Barça team will travel to London on Tuesday evening – two days ahead of schedule – due to fears of volcanic ash from Iceland drifting towards England and disrupting flight patterns. "To avoid possible disruption due to ash from the volcano Grimsvotn, the Barça first team will travel to London today at 22:00hrs [2100 BST]," a club statement said.

The eruption of Grimsvotn has already led to airlines cancelling a number of flights to and from Irish and Scottish airports.

Barça were forced to travel by bus to face Internazionale in the semi-final of last year's competition after flights were cancelled due to an ash cloud which covered much of western Europe. Inter won 3-1 at San Siro and went through 3-2 on aggregate.