The Chelsea F.C. is winning.
Chelsea F.C. . Chelsea had their first major success in 1955 , when they won the league championship . The club 's greatest period of success has come during the last two decades ; winning 18 major trophies since 1997 . Chelsea are the only London club to win the UEFA Champions League , and one of five clubs to have won all three main UEFA club competitions , first English to do so .