They came out in the top places of the four-team group which also included Skerries and Drogheda. Sandford opened up the with a 3-0 win over the Co Louth school with ben Epstein netting two drag-flicks while Matthew Tector also rolled in from the flick spot.
St Mark's, meanwhile, nicked their evenly fought contest with Skerries 1-0 - Lee Byrne on target - despite some powerful work in midfield for the North Dubliners from Stephen Rogan and Conor Colman.
Sandford showed a bit more experience to outdo Skerries 4-0. St Mark's and Drogheda played out a 0-0 tie and the Tallaght side completed the group stage with a clean sheet when they drew with Sandford 0-0 while Skerries picked up a 2-1 win over Drogheda
Results: Sandford Park 3 (Ben Epstein 2, Matthew Tector) Drogheda GS 0; Skerries CS 0 St Mark's CS 1 (Lee Byrne); Sandford Park 4 (Ben Epstein, Patrick Carey, Roland Cottle 2) Skerries CS 0; St Mark's CS 0 Drogheda GS 0; Sandford Park 0 St Mark's CS 0; Skerries 2 (Stephen Rogan, Harry Dawson) Drogheda GS 1
Table (points/goal diff): 1. Sandford Park 7pts (+7) 2. St Mark's CS 5pts (+1) 3. Skerries CS 3pts (-4) 4. Drogheda GS 1pt (-4)
* For more pics from the blitz, click here