The Derby victory against Forfar took City to the top of the table and manager Dick Campbell warned the rest of the league his side were only going to get better.
The final scoreline slightly flattered Brechin, who were made to work hard throughout the 90 minutes, but slackness at the start of both halves cost the home side dearly.
Steven Hampshire set Brechin on the road to victory after just six minutes. A long ball over the top of the defence by Scott Walker was perfectly controlled by the striker and he steered the ball past the Forfar keeper.
Forfar responded well and Brechin keeper Craig Nelson was the busier of the two as he pulled off a point-blank save from David McClune.
Forfar hit the crossbar in the 16th minute when a cross from Alan Rattray deceived the keeper and Paul Tosh should have put his side a head from the rebound, but somehow shot wide.
The Loons deservedly equalised in the 41st minute when Tosh glanced a header from a Rattray across beyond the stranded Craig Nelson.
The second half was just eight minutes old when Brechin were ahead again. Charlie King sent a tempting cross for Paul Ritchie to steer a perfect diving header into the corner of the net.
Forfar tried hard to get back on level terms but with just a minute to go Brechin were awarded a penalty when David Lowing handled in the box. Ritchie made no mistake from the spot as he sent the keeper the wrong way.
The Loons claimed a penalty themselves seconds later when Lowing appeared to be fouled in the box, but he was booked for diving.