Rondo found Garnett for a basket on a lob pass with 41.9 seconds left that turned back a late Bulls rally and handed the Celtics a 97-93 lead.
The Boston point guard also finished with nine rebounds -- just missing a triple-double as Boston broke a five-game losing streak at Chicago.
The Bulls got 26 points and 11 rebounds from Luol Deng while Joakim Noah supplied a double-double of 17 and 11 in the loss.
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