However, the relegation-threatened Tangerines fought back in the second half with Gary Taylor-Fletcher's goal, although Robin Van Persie sealed the points with 15 minutes left.
Life without football boring - Lehmann
Victory took Arsenal to within seven points of Manchester United at the top of the table to seven points, and the Gunners could further narrow the gap to a single point if they win their game in hand - against Liverpool - and beat the Red Devils when the sides meet at the Emirates Stadium on 1 May.
"Today was only three points and it could help us to keep a chance," added Wenger, who confirmed that Almunia's injury was to a knee.
"We have promised ourselves to give everything until the end of the season. There are still seven games. It is a long time - there are many games."
Lehmann admitted that he was "very surprised" to be making his 200th Arsenal appearance.
"I couldn't really think about it, I couldn't afford to be nervous," he reflected.
"I loved playing football and when you finish it's a little bit boring because you don't have this adrenaline any more but that's what came back to me. I'm quite happy about it.
"Sometimes life is about surprises. I don't know [what happens next].
"If that's my last game ever, I'm happy because we won. Let's see.
"[The gap to United] is only four points if we win our game in hand. Look at me, you never know what's going to happen in life. United have to play a lot of games in a lot of different competitions and I know from experience what that's like. It's exhausting."
Blackpool manager Ian Holloway went to see referee Lee Mason after the match because of his anger at certain decisions, including the denial of what he described as a "stonewall penalty" when Laurent Koscielny slid in on Taylor-Fletcher not long after he had pulled a goal back.
"It was very amicable," Holloway commented. "I was very calm, I can't afford not to be.
Holloway incensed by referee
"I can't describe how I feel. How that is not a penalty I just do not know, to be perfectly blunt.
"But Mr Mason has given us a couple of penalties before and he didn't see it as one, nor the handball. Those things at this level make huge, huge, huge differences. I think the man genuinely gave what he thought he could see. If he wasn't sure he couldn't give it.
"It is a bit easier not to be sure against Arsenal but I am sure they have had a few this year when they thought they should have had one.
"What annoys me is it is so easy to get it totally and utterly right - a five-second delay on a monitor."
However, Holloway added: "I'll shut up, let's get on with it and have another go against Wigan next week. There are an awful lot of points still to play for."
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