After Francois Zoko put Yeovil ahead, the Valiants needed a penalty from Tom Pope five minutes from time to secure a share of the spoils.
Aspin said: “I thought we were awful all game really and we didn’t deserve anything from the game.
“I’m happy to take a point but we didn’t deserve it as it was a very bad performance. You must defend properly first to give yourself a basis but we didn’t do that today.”
Since beating high flying Luton Town 4-0 in late December, Aspin’s side have only scored one goal in three league games.
Aspin said: “The whole performance is a concern. We didn’t make any chances today and we didn’t defend well. Yeovil made more chances against us in today’s game than any of the other teams we’ve played against since I’ve been here.
“I picked the team that played against Luton, the only difference was Gavin Gunning and it was chalk and cheese between the two performances. Everything we had in the Luton game we lacked today – we lacked tempo, we lacked energy, didn’t pass the ball well enough, everything was wrong with the performance.”
Yeovil manager Darren Way hailed his players performance but believed Port Vale’s penalty should not have been given.
He said: “The lads are a little bit deflated but I’ve said keep your heads up. From start to finish it should have been five or six but it’s hard when you come to places like this.
“I’ve watched it back again and it was never a penalty. I was speaking to the fourth official throughout the game and I said don’t let the crowd dictate decision making but I felt they did in that situation.
“He [Sowunmi] gets a touch of a ball. The direction of the ball changes. They are always going to get that at places like this but I want my players to be proud. They were up for this game today. They had to stand up to the physical battle which they did.”
Despite conceding late on, and not managing to get that crucial second goal, Way said his side played ‘fantastic football’.
He said: “The first half was probably the best away performance I’ve witnessed and their crowd started booing.
“Everything was going for us and unfortunately we just didn’t pick up the three points. Sometimes football has a wicked way of not giving you what you deserve and that was the case today.”
Watford are being linked with a summer swoop for Werder Bremen's Sweden international left-back Ludwig Augustinsson.
West Ham are reportedly set to pull out of their plan to sign central defender Alfie Mawson from Swansea this summer.