Gerard Pique's header was cleared off the line by Young, but when Rio Ferdinand reacted first, Gardner could only lash his attempted clearance into his own net.
Florent Malouda drilled a thunderous long-range strike narrowly over the crossbar, Shay Given palmed clear from Joe Cole, Didier Drogba headed over and Vincent Kompany almost sliced an attempted clearance into his own net.
But Felipe Caicedo pounced on a defensive error to equalize four minutes before halftime, slotting into the empty net after Gerard Pique missed his attempted clearance to leave goalkeeper Victor Valdes stranded.