The Hammers only bounced back into the top-flight last season, as play-off winners, but appear to have benefitted from an enforced spell in the second tier.
They have returned with a steely determination not to slip through the trapdoor again, with Sam Allardyce having assembled a squad which blends creative spark with defensive steel.
That formula has worked a treat during the opening weeks of the 2012/13 campaign, and O'Brien is confident that West Ham can build on their seventh-placed standing despite facing a daunting run of fixtures heading into the festive period - including trips to Manchester United and Tottenham.
O'Brien, who netted his first Premier League goal in Monday's 1-1 draw with Stoke, said: "We were in the Championship last year and when times got bad that's what we said our aim was, to play against the Uniteds and Spurs and teams like that.
"So we look forward to it. It's tough but that's what it's about.
"We're here to surprise one or two. That's the aim. We're not going out just to turn up and get beat and enjoy it. We're going out there to get results, like we did at Newcastle last week.
"We have nothing to lose against these teams. We can play freely and have no real pressure to get a win."
He added: "We think we're a good team. That's how we go out and play. We don't have that mentality where we're from the Championship and a newly promoted team.
"We have some quality players that have played in the Premier League for a long time. That's the mentality we play with."