The Crusaders had needed a four-try win to take a bonus point and put pressure on the Chiefs, but managed only three as the Hurricanes fought to the finish.
Defending champions Chiefs can head into their final regular-season match against the Blues on Saturday assured they have a week off before a home semi-final regardless of the outcome.
The Crusaders cemented a home playoff in the first week of the postseason but will have plenty to ponder after a disjointed display in front of home fans.
The Hurricanes were already out of the playoffs but took it to the hosts and pulled within a point in the last 15 minutes when winger Julian Savea scored a late try.
The visitors searched desperately for a late score, but jet-heeled winger Marshall dribbled a kick to the left corner in the final minutes and bolted half the length of the field to touch it over the line.
Zac Guildford and Andy Ellis scored the two early tries for the Crusaders, who enjoyed good service from in-form flyhalf Dan Carter but may hope captain Richie McCaw can slot back into the team for the playoffs after a long sabbatical.
Carter kicked two penalties and two conversions to add 10 points.
Victor Vito and Brad Shields scored early tries to keep the Hurricanes in touch.