You need a great bullpen

Pitching, pitching and more pitching.
The Indians had it in their Division Series victory over the Yankees.
The Yankees' arms were either old and worn out or young and burned out.
The Indians' starters' were far superior to the Yankees, even No. 4 starter Paul Byrd, who handcuffed the Yankees in Game 4. Before that, C.C. Sabathia and Fausto Carmona did their job. They got the ballgame to the bullpen.
The real difference was the pen. The Indians' pen allowed only two earned runs in the series. Rafael Perez, Rafael Betancourt, Jensen Lewis and even shaky Joe Borowski did their jobs baffling a solid Yankees' lineup.
On the other side, the Indians hammered Chien-Ming Wang TWICE. The Tribe was beating on Roger Clemens before he was suddenly hurting and needed to be removed from the game. Only Andy Pettitte was effective among the Yankee starters.
The Indians also got plenty of key two-out RBI hits.
Timely hitting and plenty of pitching, including a strong bullpen.
It worked in the Division Series.
The Indians will need more of the same against Boston, which has its rotation set with Josh Beckett, Dice-K Matsuzaka and Curt Schilling.