The visitors started well with two clear cut chances in the opening minutes.
Penicuik had their first opportunity on 11 minutes when a corner fell to Gay, who crossed the ball to S Scott but he failed to hit the target.
On the half hour, a neat move by Penicuik saw Somerville lay the ball back to Jones but his effort flew high over the crossbar.
At the other end a long range strike by Scott for Swifts went wide.
In the 44th minute, a mix up between Easton and Young gave Scott an opportunity, but more by luck than design, the danger was cleared.
One minute later, Jeanfield had the ball in the net bt it was ruled offside.
In injury time, Swifts centre back Deans was red carded for abusive language and seconds after, Forbes headed home a Gay corner kick.
Penicuik had two golden opportunities to score in the 56th minute, when S Scott saw his strike superbly saved by keeper Mitchell and three minutes later when Jones burst into the box only to see Mitchell turn away his goal bound strike.
The ball, however, was then fed back to Somerville who made no mistake to double Penicuik’s lead.
Minutes later, another great pass set S Scott free and he curled his shot over keeper Mitchell and into the top corner of the net.
In the 71st minute a fine passing move by Jeanfield was thwarted by a superb one handed save by Easton.
Five minutes later Penicuik substitute Lough skied the ball over the bar when it seemed easier to score, however, he redeemed himself one minute later slamming home from inside the box.
In the dying minutes, Swift’s Smith received two yellow cards.
Penicuik: Easton, Forbes, Noble, Hume, Young, Gay, MacDonald, Jones, Somerville, S Scott, K Scott Subs: Janczyk, McCallum, Barr, Connolly, Lough.