The defending world champion Angels returned from the All-Star break on the rise, winning five straight games. But the Orioles stalled that momentum, sweeping their first four-game series from the Angels since Sept. 24-26, 1965.
Segui provided the game's biggest blow in the sixth when he turned a 3-0 lead into a seven-run cushion with his fifth homer of the season. It was his first grand slam since Sept. 15, 2000 against the New York Yankees.
The offense was more than enough for Johnson (8-4), who surrendered one run and six hits in 7 1/3 innings.
Baltimore nearly squander a 7-1 lead in the ninth when the Angels scored five times, highlighted by Scott Spiezio's three-run homer.