A 3-1 win against Dundee followed by a 0-0 draw at Ross County pushed the Saints six points clear of Dundee at the foot of the Scottish Premier League, and they capped off a successful week by booking their place in the fifth round of the William Hill Scottish Cup.
"It's back to business in the league now and we have started to turn things around there too, we are all looking forward to the next run of games and getting more points on the board," said Robertson.
"We had a bad run in the league and it was hard turning up to games where you don't get the rub of the green - it's been a good week for results and hopefully we can continue from here."
The former Cowdenbeath midfielder was delighted after notching his first goal for the club in fantastic style.
Robertson has been encouraged to shoot more often by St Mirren boss Danny Lennon and the advice paid off as his 25-yard strike found the bottom corner.
"I could hear every single person in the stadium shout 'take a touch', I get a lot of criticism for not shooting enough - sometimes if you buy a ticket you win the raffle," he added.
"We could and probably should have had a few more against Brechin, failing to score in the second half kept the game tight and 2-0 is a fragile lead."
Brechin manager Ray McKinnon was proud of his side's determined display during their cup exit at St Mirren Park.
A spirited second-half rearguard by City prevented St Mirren from building on their two goal advantage.
"We were trying to sit in and hit the on the counter-attack, but the opening goal put us under pressure and then they scored a wonder goal before half-time," said McKinnon.
"I have a good honest bunch of lads and I think they competed well and showed a desire to win - they gave everything they had.
"St Mirren are a good side though and we thoroughly deserved their win."