Goals from Louis Saha and Emmanuel Adebayor's penalty put us in control after 33 minutes of this latest North London derby.
But it all changed when Bacary Sagna headed Arsenal back into the game after 40 minutes.
Two minutes later and Robin Van Persie levelled and the Gunners clicked into overdrive in the second half, firing home three more goals in 23 minutes for an unassailable 5-2 lead.
"We went two up but even then I couldn't stand here and say I felt comfortable," reflected Harry.
"I felt that they had a few chances and that if they got a goal back then they were playing through us a bit and outnumbering us in the middle of the park.
"I just wanted to get to half-time at 2-0 up, if we could do that then we'd be okay.
"Last season they were 2-0 up at half-time and we ended up beating them 3-2. All of a sudden, we found ourselves at 2-2. In fact, we could have gone behind.
"We changed how we were playing in the second half. I felt we needed to thicken up in midfield, but we didn't defend well all over the park.
"I knew it would be a tough game but when you are 2-0 up, you couldn't ask for a better position to be in.
"As I said though, even at 2-0, we didn't look as solid as I would like us to be. It was a big problem.
"In the end, we've had a bad day, but we have to keep going."