Victory would have put Villa five points clear of the Barclays Premier League bottom three.
However, after the impressive Charles N'Zogbia gave Villa a deserved 55th-minute lead, the visitors were gifted an equaliser when midfielder Fabian Delph flicked Bryan Ruiz's corner into his own net with a header 11 minutes later.
Jol said: "If you play against a team like Aston Villa they will be full of energy and before the match we saw the stats and the fact they had three wins and one defeat in the last four.
"They're doing well, they can put you under pressure so it was good for us to see Gabriel Agbonlahor was not playing because he has real pace and penetration.
"They were hot and cold and then we had a spell in the second half where Villa deserved a goal and they got it.
"We had to change things and luckily enough we scored an equaliser and got to 40 points because that was our target.
"If you look at the other teams, such as Villa, they would like to swap with us. Since January 1 we've had three defeats and seven or eight wins and draws, so we've done ever so well.
"I'm a happy customer. We've got 40 points, the results were okay for us and that's fantastic."