Krause made another transaction in 1988 to which Jordan strongly objected. It was clear that the Bulls needed a center if they were to contend for a title, so Krause dealt Charles Oakley to New York for Bill Cartwright. Oakley, who happened to be Jordan's best friend on the team, was extremely tough, particularly on the boards and on defense. When the Pistons came after Jordan with their physical players, Oakley was his bodyguard. Cartwright was a true center, unlike the power forward Oakley, but was much older. Although Cartwright did not have Oakley's reputation as a lockdown defender, he was very effective at preventing opposing centers from dominating games, and was a more capable inside scorer. Jordan despised the trade, not only because of the players involved but also because of how they learned of it: via television, while he and Oakley were on their way to Las Vegas to see a Mike Tyson fight. Cartwright turned out to be everything the Bulls needed, however, providing a presence in the middle for all three Bulls championships from 1991–1993. Perhaps most importantly, Cartwright proved to be the league's best center at defending Patrick Ewing, the New York Knicks' star who was the key player on the Bulls' most important early-1990s conference rival.