
Eriksen was denied the chance to break the deadlock from the spot 20 minutes in when a penalty decision was overturned by VAR, but the Danes soon took the lead through Pierre-Emile Hojbjerg.
The combative midfielder allowed a clever pass from Jonas Wind to run across his body before rattling home a right-footed shot to open the scoring in the 26th minute.
The second goal came two minutes later when Eriksen wrong-footed the San Marino defence with a sublime backheel into the path of the onrushing Joakim Maehle, who took the ball past the keeper and slotted home a simple finish.
Making his 123rd appearance for Denmark, Eriksen notched up his second assist in the 40th minute, teeing up striker Wind to score, and his third came in second-half stoppage time when substitute Yussuf Poulsen got the slightest of touches to a speculative cross to seal the win.
The victory moves Denmark to second in the group on 10 points after five games, two behind leaders Finland and ahead of third-placed Slovenia on goal difference.