The visitors’ record so far in the league this season has been more than impressive and Saints knew they had to play well to get at least a draw.
With Sauchie playing down the slope, it was obvious they wanted to set the pace of the game and took control from the off.
On four minutes they opened the scoring with good work through the middle and McTaggart fired a shot past Cargill in off the post.
Sauchie continued to dominate play with quick passing and Saints were put under pressure even when they had possession.
The first real break forward for Saints on 21 minutes saw Schiavone get a great cross into the area but Sibanda headed over the bar.
A minute later Millar made it 2-0 for the visitors.
Sauchie continued to dominate.
Good work in 28 minutes gave Millar a second chance and he scored with a low well placed shot just inside Cargill’s left hand post.
It continued to go Sauchie’s way when in 36 minutes a foul was conceded in Saints area and Morgan stepped up to make it 4-0 with a shot high past Cargill.
The pace set by Sauchie during this period was very fast.
With four goals scored the pace eased and Saints managed to keep it at that to the break.
The first 10 minutes of the second half saw Sauchie pressurise the home team some more and were unlucky in 52 mins when a fierce shot came back off the bar to be cleared for a corner.
Saints did have more of the play during the remainder of the game but did not create any decent opportunities to reduce the deficit.
Sauchie had achieved their winning score in the first half and allowed Saints a certain amount of freedom to get forward.
The visitors look near certainties to get promotion back to the Super League.
On Saturday Saints travel to Forfar West End.
Saints -Cargill, Duffy, Graham, Hendry, Wedderburn, McInnes, McPhie, Nutt, L Schiavone, Sibanda, Buchan.
Subs - Perrie, Falconer, Fleming, C Schiavone, Ireland.