Michail Antonio gave the Hammers the lead at half-time. But second half strikes from Joël Veltman, Pascal Groß and Danny Welbeck saw the Seagulls round off their campaign in style at the Amex.
The win, which also denied the Irons a spot in next season’s UEFA Europa League, saw ninth-placed Brighton record their highest-ever Premier League finish with a record points total of 51 from 38 matches.
March said: “If you look at some of the teams we’ve finished above, it’s a big achievement.
“If you had said ten, 12 games ago that we would be ninth with 51 points, everybody would have snapped your hand off for that.
“It’s all the effort and hard work over the previous two thirds of the season that has all come together. We deserved it.
“We’ve got to come in and improve on that next year. If we stick with our main group of players that we’ve got and add a few players, I think we’ll be in good stead to do that.”
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