Elliot Bradbrook put Dartford 1-0 up in just the 6th minute with a header into the top corner.
The Saints equalised 5 minutes before half-time when Charlie Walker finished off a well-worked corner routine.
What turned out to be the winner for the Darts arrived on the hour-mark when a free-kick was taken short to Lee Noble, back to Lyle Della-Verde and his cross was deflected in by the Saints` Tom Bender.
There was a tense final half-hour with Dartford doing just enough to win the game against an impressive St Albans side.
Hemel Hempstead Town have climbed to second spot after a 1-0 win at the FutureFuel Stadium against East Thurrock United.
The only goal came after 26 minutes, scored by Charlie Sheringham, son of Teddy, clinically finishing in a fashion his former England star dad would be proud of.
Hemel moved above Chelmsford City after Will Richards’ 90th minute volley gave Chippenham Town all three points after City had come from 2-0 behind at Hardenhuish Park.
David Pratt put the hosts ahead on 27 minutes as Sam Beasant missed a long-throw before Scott Twine doubled the Bluebirds’ advantage with an unstoppable effort from distance in the 42nd minute.
Chelmsford`s Chris Dickson then had a 57th minute penalty saved but the rebound was turned home by Michael Spillane to give the Clarets a chance.
Dickson then netted a long-range lob on 88 minutes to salvage what the visitors thought would be a point.
But Richards had other ideas as he reacted quickest to a loose ball and bundled home a corner to restore Chippenham’s lead in stoppage time.
Braintree Town are fourth but they too were beaten on Saturday by a visiting Havant & Waterlooville outfit who are now eighth.
Jason Prior grabbed a hat-trick of penalties for the Hawks at Cressing Road.
After a goalless first half, Prior scored twice from the spot in the opening 8 minutes of the second period.
Sub Marcel Barrington reduced the arrears on 66 minutes, but Prior converted his third penalty 11 minutes from the end.
Truro City and Welling United complete the top seven, but neither managed a win.
The White Tigers were held to a 1-1 draw at Treyew Road by lowly newcomers Bognor Regis Town, whose Ibra Sekajja cancelled out Ben Gerring`s 16th minute opener for the hosts in the 36th minute.
The Wings went down to a 2-1 Park View Road defeat to a Wealdstone side who are now tenth.
Ryan Sellers gave the visitors a 39th minute lead that Danny Green doubled 4 minutes after half-time from the spot after a foul on Abobaker Eisa.
Just before the hour-mark, Welling were reduced to ten-men with a straight red card for Ben Jefford for a late challenge.
However, it was the ten-men who scored next with a Jack Parkinson header after 65 minutes, but the Stones held on.
Gloucester City pushed Poole Town further towards trouble at the wrong end of the table after winning 3-0 at Tatnam.
It was 0-0 at the break, and then Karnell Chambers broke the deadlock to give the Tigers a 54th minute lead.
Joe Parker added a second on 66 minutes and 6 minutes from time, Jack Storer completed a comfortable win for Tim Harris` side.
Hungerford Town were forced to play with ten-men for over 85 minutes against Eastbourne Borough at Bulpit Lane.
Diak John received a straight red card for deliberate handball in just the 5th minute, but Lewis Ward saved Lloyd Dawes` penalty.
The Crusaders battled hard but conceded a second spot-kick in the 77th minute after Sergio Torres was upended in the box with Matt Drage making no mistake.
Whitehawk remain firmly rooted to the bottom of the table and now nine points adrift of the safety-mark after losing 1-0 at the Woodspring Stadium to a Weston-super-Mare side who are now sixteenth.
Gethyn Hill`s goal right on the stroke of half-time eventually proved enough for the Seagulls.
Concord Rangers made a late rally to rescue a point against Oxford City, scoring an 86th minute equaliser through Amos Nasha Junior to cancel out Rob Sinclair's earlier effort on the hour-mark in an otherwise turgid 1-1 draw at Marsh Farm.