Northern Ireland claimed their first win in the World Cup qualifiers with an easy victory over the minnows.
David Healy struck low into the net for his opening goal of the campaign and a blistering shot from Grant McCann made it 2-0 at the break.
Kyle Lafferty slotted in from close range for the third before San Marino's Mauro Marani was red-carded for striking Michael O'Connor in the face.
A cheeky Steve Davis finish 15 minutes from time sealed a vital three points.
O'Connor came in for his first N Ireland start in place of the suspended Jonny Evans and the midfielder should have opened his goalscoring account on four minutes but he sent his eight-yard header over.
The game quickly progressed into a predictable pattern of the homeside attacking and San Marino soaking up the pressure.
Healy toe-poked wide and Davis curled a shot straight at keeper Frederico Valentino before a deserved opener arrived on the half hour.
606: DEBATE
George McCartney started the move with a surging run down the left before McCann slipped the ball to Healy, who created the space to crack low and off the legs of Simone Bacciocchi and Valentino before finding the net.
Healy wasted a good chance two minutes later when he side-footed wide after Valentino punched his clearance straight at the Sunderland striker.
McCann doubled the lead two minutes before the break, latching on to Healy's lay-off before blasting into the corner from 16 yards.
With the minnows offering virtually nothing in attack the game was effectively settled by half-time.
It was now a case of how many N Ireland could score and Lafferty made it 3-0 after 56 minutes.
Valentino pushed Healy's shot into the path of the Rangers forward, who tapped into an open net. San Marino's task was already beyond them before Marani was shown a straight red card after 63 minutes for striking O'Connor after the pair tangled in midfield.
N Ireland were now enjoying themselves and Lafferty provided the cut-back for his Ibrox team-mate Davis to cheekily flick the ball in at the front-post for the fourth goal in the 75th minute.
The chances continued to the final whistle but the job was done and N Ireland's campaign got the kick-start it desperately needed.
Northern Ireland: Taylor, Baird, Hughes, McAuley (McGivern 60), McCartney, Gillespie, Davis, O'Connor, McCann (Paterson 72), Healy, Lafferty (Feeney 82).
Subs not used: Mannus, Gault, Shiels, Thompson.
Booked: McAuley, McGivern
Goals: Healy 30, McCann 43, Lafferty 56, Davis 75
San Marino: Federico Valentini, Carlo Valentini, Mauro Marani, Albani, Della Valle, Bacciocchi, Bonini (Fabio Vitaioli 77), Michele Marani, Manuel Marani (Cibelli 86), Selva (Matteo Vitaili 47), Vannucci.
Subs not used: Simonlini, Valli, Nanni, Andreini.
Sent off: Mauro Marani 63
Booked: Della Valle, Carlo Valentini
Referee: Petteri Kari (Finland)
BBC Sport Player Rater man of the match: N Ireland's Grant McCann 8.10 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.
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