Two goals in the opening seven minutes sent Southend on the way to a thrilling 3-2 victory and only their second success over Port Vale in the last 10 meetings between the clubs.
Centre-back Mark Phillips buried a powerful header into the roof of the net from Lee Sawyer's right-wing corner to open the scoring in the fifth minute.
And the lead was quickly doubled when Liam Dickinson spun 20 yards out to drive a terrific left-foot finish low inside Stuart Tomlinson's right-hand post.
Vale were back in it when Doug Loft raced onto a slide-rule pass from Gary Roberts to lift the ball over the advancing Glenn Morris' dive in the 25th minute.
But Southend were two goals to the good again four minutes later as an ambitious 30-yard shot from Ryan Leonard was misjudged by Tomlinson and the ball squirmed under his dive.
Loft buried his second, sending Morris diving in the wrong direction from a 50th-minute penalty after Dickinson had pushed Gareth Owen to the ground.
But Southend, with Phillips outstanding, defended solidly after that to secure their second away win of the season and inflict Vale's first league defeat.
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