By Robert Woodward
LONDON, Nov 26 (Reuters) - A late goal by Basel's Mohamed Salah condemned Chelsea to a shock 1-0 defeat in the Champions League on Tuesday although the 2012 title winners still qualified for the knockout stages.
Basel's double over the English side gives them eight points in Group E, one fewer than Chelsea. They visit Schalke 04, who drew 0-0 with Steaua Bucharest and have seven points, next month to decide which one joins Chelsea in the last 16.
Barcelona, without Lionel Messi but already qualified, lost 2-1 at Ajax Amsterdam after conceding two first-half goals but almost turned the game around once the home side's Joel Veltman was sent off three minutes into the second period.
Xavi pulled a goal back but Ajax held on and travel to AC Milan next month with all still to play for. Milan were too strong for Celtic, winning 3-0 in Glasgow, and have eight points to Ajax's seven in Group H.
Three sides in Group F - Arsenal, Napoli and Borussia Dortmund - all still harbour hopes of qualifying.
Arsenal have 12 points after beating Olympique Marseille 2-0 at home thanks to a double from England midfielder Jack Wilshere while Dortmund, last season's runners-up, join Napoli on nine points after beating the visiting Italians 3-1.
Arsenal travel to Napoli on Dec. 11 while Dortmund play at Marseille, who have yet to earn a point.
In Group G, Zenit St Petersburg and Porto still have a chance of joining section winners Atletico Madrid in the last 16. Zenit drew 1-1 at home to Atletico to move on to six points while Porto have five after drawing 1-1 with Austria Vienna. (Reporting By Robert Woodward)