(CNN) — MIchael Phelps rounded off his record breaking career with his 18th Olympic gold medal as part of the winning U.S. 4x100m medley relay squad today.
It was his fourth gold in London — two individual, two team — and extended his all-time Games record to 22 medals.
Phelps swam the third butterfly leg and helped overhaul surprise leaders Japan to give Nathan Adrian a small lead for the freestyle finish.
They won in three minutes 29.5 seconds from Japan with Australia in third place.
