The tenacious midfielder admits that Spurs had a "bad day" as Dimitar Berbatov's goalscoring return to White Hart Lane saw the club lose ground in the race for the top four.
Spurs are wary of mimicking last season, when they capitulated as the campaign drew to a close and ultimately missed out on qualification for Europe's top table – despite finishing fourth.
Dimitar Berbatov consigned his former club to its second successive league defeat on Sunday, with Andre Villas-Boas's men now just four points clear of Arsenal having played one game more. The Gunners were seven points adrift after the north London derby but have since capitalized on Spurs's consecutive losses.
"We’re all disappointed," Parker told the club's official website. "You don’t want to make excuses but we just a looked a bit flat. Having said that, I don’t think we deserved to lose the game. They hit us on the break and scored a goal, so it was difficult. Mark Schwarzer then produced an unbelievable save at the end. It was one of those days for us.
"We need to stay positive now, that’s the main thing. I’ve always said that you can’t mope around in these situations. Okay, it was a bad result, but we need to look forward now. It’s not ideal how it went and everyone’s frustrated, us, the fans, but we’re still in a good position and we need to keep going."