Two strikes in the space of three minutes from Gary Innes and John MacDonald got the An Aird side off to a perfect start, and though Robert Walker deservedly pulled one back for Bute just before half time, MacDonald's second of the afternoon only t
hree minutes after the break gave the island side too much of a mountain to climb.
Bute went into the game on a high after their memorable Camanachd Cup quarter-final win over Inveraray seven days previously, but the hosts were almost immediately put on the back foot by a Fort side keen to show they were a better side than their own Camanachd Cup last eight display - a 3-2 extra time win at North Division One Kinlochshiel - might suggest.
And the home side were put on the back foot almost immediately, Innes tempting Bute full back David MacDonald into a foul on the edge of the D with barely half a minute on the clock - and from the free hit, Bute keeper Kevin Queen had to look smart to parry both Bryan Simpson's shot and Gordy MacKinnon's follow-up.
Good close marking from the Bute defence prevented MacDonald getting a clear sight of goal in the fourth minute, the Fort man's shot instead trickling wide for a bye hit, but the men in yellow were smiling a short time later when a shy from the left seemed to catch the Bute defence on the hop, and Innes ignored loud claims from the hosts for a handball offence to smack the ball past Queen and into the net.
And Bute's task was made even more difficult within seconds of the restart when Fort won possession straight from the throw-up, and MacKinnon and Simpson combined to set up MacDonald, who fired a rocket past the unsighted Queen from 20 yards to double the visitors' lead.
Matters might have worsened even further for the home side within a minute of the restart, but this time Innes sent his shot well wide of target after being teed up perfectly by MacDonald from a Simpson cross on the right.
But having only narrowly escaped the loss of three goals inside five minutes, Bute knuckled down and slowly but surely began to gain a foothold on the game; Stewart Strathie had the islanders' first shot on target on 21 minutes after a Graham Fisher shy, but his looping effort from a lay-off by captain Hector Whitelaw was just too high.
Walker hammered a first time shot just wide of Fort keeper Scott McNeil's left hand post as Bute showed they still had plenty of fighting spirit left - and hopes that a famous comeback might et be possible were stoked still further six minutes before the break, when Walker's persistence won him two free hits on the edge of the visitors' penalty area - and from the second, the Bute man - who scored a hat-trick in that Inveraray cup win - lashed the ball into the far corner of the net.
Bute finished the first 45 minutes very definitely on top, captain Whitelaw scooping a shot over the crossbar after an excellent passing move before Walker fired just wide in the last attack of the half, but despite those missed chances the hosts went into their half time huddle in an optimistic frame of mind after their dreadful start to the game.
But those hopes were dealt a hammer blow within three minutes of the restart when a Fort free hit on the right wing was played deep to MacKinnon on the left wing, and MacDonald ghosted in at the far post to sweep MacKinnon's return pass into the net.
Simpson ought to have done better from a MacKinnon cutback only a minute later, but failed to get a proper hit on the ball and saw his effort trickle tamely wide of Queen's goal.
But Fort William were determined to put the game well and truly out of the reach of their hosts, and Simpson saw two further efforts blocked by Bute defenders after Niall MacPhee galloped clear down the right wing before Queen eventually whacked the ball clear to ease the burden on the hard-pressed home defence.
Strathie and Walker combined to put the Fort William defence under some real pressure on 65 minutes, but neither man could get his shot away and the danger was eventually cleared; Strathie tried his luck from distance two minutes later but saw his shot fall a couple of feet wide of McNeil's goal.
At the other end only a superb full-length diving save by Queen prevented Simpson making the points well and truly safe for the visitors on 70 minutes, and MacKinnon wasted another golden opportunity to make the game secure for the men in yellow when he scooped his shot high over the bar five minutes later.
Brian Liddle came on in place of Roberto Zavaroni for the final 15 minutes as Bute hoped a pair of fresh legs might turn the game their way, but an ambitious John McCallum effort from 25 yards, the ball clearing the crossbar by a couple of feet, was the best the home side could do.
Fort William, on the other hand, knew exactly what they had to do to end any hopes of a Bute fightback, and Drew McNeil's men used all their experience to take the sting out of the game in the final stages.
Mark Lawrie might have added a fourth for the visitors seven minutes from the end, but by then it was clear that a second famous win on successive Saturdays was going to be a step too far for Bute on this occasion, and the Fort side saw out the last few minutes of the match in relative comfort.
* Bute's second team saw their South Division Two match away to Kyles Athletic on Saturday postponed due to the continuing effect of the swine flu outbreak on the Tighnabruaich team's squad.
* Neither Bute team has a game on Saturday, June 20 due to the Marine Harvest Festival of Shinty.