"Earlier in the week it was a bit disappointing coming off the loss to Manawatu but the boys have recovered," O'Connor said, referring to last Sunday's 29-3 loss to the Turbos in Palmerston North.
Blues openside flanker O'Connor missed the Turbos match with a niggly hip injury but he's confident Magpies physio Mark Nicol will have him ready for action by kickoff.
For the first time this season O'Connor, 25, will start at No 8, a position he finished a match in earlier in the campaign.
Today's game is one he doesn't want to miss.
"Not only have we got a chance to keep the shield for the summer. We've also got an opportunity to nail a home semifinal and secure a home final," O'Connor said.
A 2009 Under-20 World Cup winner, O'Connor is anticipating the Stags to be physical.
"They pride themselves on their forward play and physicality at the breakdown. We have to match that and start well.
"We know Southland can grind out wins. We have to push them early so they're chasing us," O'Connor added.
Magpies fans will be pleased to hear O'Connor and co have placed a huge emphasis on starting well.
A repeat of last weekend's poor start, which saw them trailing 17-0 at halftime, could be costly.
All week the Magpies have stressed the need to up the urgency with their physicality at the breakdown. If they don't, the likes of Stags captain and former All Blacks prop Jamie Mackintosh and the Highlanders trio of lock Josh Bekhuis, No8 Elliot Dixon and flanker John Hardie will gain the upper hand, and if players of this calibre are given too much freedom the Magpies could be in for another tough day at the office.
Improved accuracy on defence and improved discipline must also be achieved by the Magpies.
The Magpies missed 33 tackles against the Turbos, 25 more than their hosts and conceded 15 penalties, five more than the Turbos.
Stags first five-eighth Lima Sopoaga has had one of his more consistent seasons with the boot and if his radar is on target again the Magpies will be foolish to concede too many penalties.
Stags centre Mark Jackman, who scored 66 points in 31 first class games for the Magpies between 2008 and '11, will be eager to prove he should never have been let go by Magpies coaches Craig Philpott and Danny Lee.
However, he is likely to find the Magpies midfield defensive pair of Jason Shoemark and Robbie Fruean as tough as any he has come up against this season. It's interesting Stags head coach Brad Mooar has opted to have Cardiff Vaega on the subs bench.
This midfielder has caused problems for the Magpies in the past and he will have to be marked closely when the collar is slipped off him.
With fine weather expected and McLean Park in tip top order, there's every chance the Magpies will again turn on some entertaining razzle dazzle on their way to maintaining this season's unbeaten home run. Should the Magpies win, it will be the first time they have won all their home round robin games since the ITM Cup format was introduced in 2010.