The Sonics and the (then San Diego) Rockets entered the league together in 1967. They wouldn't meet in the playoffs until 1982, but when they did, the Sonics dominated Houston.
Between 1980 and 2000, the Sonics defeated the Rockets five straight times in the playoffs before losing in their final meeting in 1997.
Of course, during that same period they lost five straight times to the Lakers in the postseason. As with most things in Seattle basketball history, no great accomplishment went unpunished.
SONICS vs ROCKETS
1982 -- WON, 2-1, first round
1987 -- WON, 4-2, conference semifinals
1989 -- WON, 3-1, first round
1993 -- WON, 4-3, conference semifinals
1996 -- WON, 4-0, conference semifinals
1980 -- LOST, 4-1, conference finals
1987 -- LOST, 4-0, conference finals
1989 -- LOST, 4-0, conference semifinals
1995 -- LOST, 3-1, first round
1998 -- LOST, 4-1, conference semifinals
Despite the seemingly one-sided history with the Rockets in the playoffs, the games were usually nail-bitters. Three out of the five series victories were decided in overtime, including the epic double OT battle in 1987, a game Sonics fans everywhere will always be thankful for.