It took the hosts less than a minute to score their first try, as Peter Mata'utia danced past the Samoan defence before releasing Cooper Cronk to ground in the corner.
Tim Simona then powered his way past Inglis to put the visitors on the scoreboard for the first time in the match.
However, the Aussies resumed their dominance with three tries in 10 first-half minutes from Inglis, Daley Cherry-Evans and David Klemmer to put them fully in control at the break.
Ben Robert made the scoreline a little more respectable with Samoa's second try three minutes into the second half, but Cronk scored his second try of the match in the 64th minute to extend Australia's lead once more.
Coming into the game, Samoa knew that they had to win by nine clear points to progress to the final, but the deficit didn't dampen their spirits, as David Fa'alogo crashed over the line with nine minutes remaining.
However, two late tries from Josh Papalii and Josh Mansour made sure that Australia will enter next week's final in high spirits.