LONDON: Lionel Messi responded to Cristiano Ronaldo’s hat-trick for Real Madrid on Tuesday by scoring a treble of his own as Barcelona thrashed Ajax Amsterdam 4-0 in their Champions League Group H opener at Nou Camp.

The Argentinian opened his account with a first-half free-kick and then struck twice more either side of a Gerard Pique header. Ajax missed a chance of a consolation goal when Victor Valdes saved Kolbeinn Sigthorsson’s penalty after a trip by Javier Mascherano.

Messi has scored a record four hat-tricks in the Champions League and totals 62 goals in 80 games, second only to Raul Gonzalez (ex Real Madrid and Schalke) who scored 71 goals in 142 appearances.

AC Milan left it late to secure a 2-0 win over Celtic. The Scottish champions were on course to leave the San Siro with a hard-earned point until an Emilio Izaguirre own-goal in the 82nd minute. Sulley Muntari ensured victory three minutes later after Fraser Forster pushed a Mario Balotelli free-kick against the post.

Jose Mourinho’s first Champions League match back at Chelsea ended in a shock defeat as Basel came from behind to win 2-1 at Stamford Bridge.

Oscar put the Blues in front on the stroke of half-time with virtually their first chance but they lacked cutting edge to add to that lead. Mohamed Salah levelled in the 71st minute with an angled strike and when Marco Streller glance-headed the winner from a left-wing corner eight minutes.

This was Chelsea’s first home defeat in the group stages since 2003 and the first time they had ever lost their opening match in the groups after three draws and eight wins previously.

Mourinho said: “After their second goal we tried hard but emotionally this is not a very mature team. They reacted with some heart but it was not enough.

“I’m the manager. I’m responsible for everything especially for the bad results and in the bad moments. I want everyone to keep calm and let me be responsible. Tomorrow I will not wake up with a smile on my face. But I have to wake up and work hard to get three points against Fulham on Saturday.”

Schalke had a much easier time of it at home to Steaua Bucharest, claiming a 3-0 win. Atsuto Uchida opened the scoring after 67 minutes, with Kevin Prince-Boateng (78) and Julian Drexler (85) adding the gloss.

Napoli were 2-1 winners at home over last year’s beaten finalists Borussia Dortmund in Group F. It could have been worse for Jurgen Klopp’s side, who lost goalkeeper Roman Weidenfeller to a red card just before the interval following goal-preventing handball outside the area.

Napoli were already ahead through Gonzalo Higuain’s 29th minute effort and doubled their advantage through Lorenzo Insigne in the 67th minute. Dortmund pulled one back in the closing moments when Camilo Zuniga put the ball past his own keeper.

Arsenal joined Napoli on three points following a 2-1 win of their own over Marseille at the Stade Velodrome. Theo Walcott (65) and the in-form Aaron Ramsey (84) got their goals, before an Andre Ayew penalty in added time reduced arrears.

In Group G, Hulk’s fine finish was not enough to stop Zenit St Petersburg going down 3-1 at Atletico Madrid. Hulk’s 58th-minute strike was the pick of the day, cancelling out Miranda’s opener, but Arda Turan and Leo Baptistao were on target to render it irrelevant.

Porto were also victorious, edging FK Austria 1-0 thanks to Lucho Gonzalez’s goal 10 minutes into the second half.