Bill "Moose" Skowron, who was a key part of four World Series titles with the Yankees, died yesterday of congestive heart failure at 81 after a lengthy illness outside of Chicago.

The first baseman hit .282, with 211 home runs and 888 RBIs in 1,658 career games, but he was perhaps best remembered for his performance during the postseason.

Skowron hit eight home runs in 39 career World Series games. He hit a three-run shot in the eighth inning of the Yankees' Game 7 win over the Milwaukee Braves in the 1958 World Series and also drove in the game-winning run with a 10th-inning RBI single in Game 6 of the same Series to force the final game.

"There weren't many better guys than Moose," Yogi Berra said of the six-time All-Star. "He was a dear friend and a great team man. A darn good ballplayer, too. I'm going to miss him."

Among Skowron's other playoff heroics was a seventh-inning grand slam off Roger Craig and the Brooklyn Dodgers in 1956. He also had a leadoff homer in the fifth inning off Vernon Law in 1960, when the Yankees overcame a four-run deficit at Pittsburgh to take a 7-4 lead only to lose 10-9.

"Moose could really hit the baseball — especially home runs to right field," former roommate Bob Turley said. "I was glad Moose was on my team because he always wanted to win."

Skowron won a fifth title with the Dodgers in 1963 and was an annual presence at Old-Timer's Day in The Bronx.

"He always had positive things to say," Derek Jeter said of his conversations with Skowron. "He would always come over and comment on how you are playing or how things will turn around. He was just always positive."

"Moose will always be remembered as being one of the key members of the Yankees' dynasties in the 50s and early 60s," owner Hal Steinbrenner said in a statement. "He was a winner in every sense of the word, and someone the Yankees family cared deeply for. Baseball lost one of its finest ambassadors, and on behalf of the entire organization, I extend my deepest sympathies to his wife, Cookie, and his entire family."

dan.martin@nypost.com