Victory over Newcastle on Saturday saw Arsenal return to the top of the table by three points ahead of Manchester City, though having played a game more.
A win against Fulham this weekend before Manchester City play will take Arsenal six points clear.
Asked if he was impressed by Arsenal on Saturday, Pennant, on behalf of BetBrain, told Tribalfootball.com: "Not really.
"I think if they don't score from that corner I don't know what would've happened. They tried it three times, didn't succeed and succeeded on the third. If they didn't score that, I couldn't see them scoring. And that's against, at home, against a Newcastle team which is in a bit of a free fall and a bit of a disarray at the moment.
"I was expecting an easy 3-0 win.
"You know, Man City now are right on their heels and obviously they win the game, they go back top (sic). But yeah, the pressure is really getting to them and you can kind of see it in the performances."
On Arsenal potentially going six points clear this weekend, Pennant also said: "It's a really tough one. I think Arsenal's fixtures are very favourable compared to Manchester City's.
"But let's put into context of how Arsenal are playing currently and how Man City are playing. Man City are on this run of form, which they seem to do every single season, every year.
"The last 10 games they just go into robot mode, just go into a mode where they just win, win, win, win, win. Kind of Arsenal are doing that now, but scraping. They're not comfortable. It's scraping over the line."