Albion's fifth-successive league win at The Hawthorns, moved them five points clear of third-placed Nottingham Forest.But it was a hard-fought success as Charlie Adam had given Blackpool the lead with his 14th goal of the season in the sixth minute before Ishmael Miller equalised seven minutes later on his first start for 15 months following a cruciate knee ligament injury.
Robert Koren then fired Albion ahead with a 25 yard drive in the 53rd minute before substitute Brett Ormerod headed Blackpool level again in the 72nd minute.
But Dorrans struck for the 14th time this season to finally end Blackpool's challenge.
Di Matteo said: "He is quite a composed person when it comes to taking penalties and he is quite cool.
"The best players in the world have missed penalties and I am very pleased that he scored.
"We are in a good position now but there are still so many games left to play.
"I will just settle for promotion whether it is automatic, play-offs, whatever it is.
"But as you could see against Blackpool, every game is tough to win.
"Blackpool played some excellent football and they made it very difficult for us."
Having found a run of form at home, Di Matteo hopes Albion can continue to make The Hawthorns a fortress during the promotion run-in.
"It doesn't matter where we get the points from," added Di Matteo.
"But we looked at the fixture list and knew we had seven of the final 12 games at home and we knew the importance of the home games.
"I am very pleased that we have managed to win the first two at home."
Blackpool boss Ian Holloway was full of praise for his side's display but was unhappy with the decision of referee Jon Moss to award the decisive penalty after Joe Martin fouled Giles Barnes.
Holloway said: "It was a foul but Giles Barnes said to Joe Martin that it was outside the box. But he gave it, so you have to get on with it.
"Joe is 21, he made a rash tackle, it was a foul.Was it inside? Obviously it was because they scored the winning goal from it, say no more.
"I thought we showed terrific belief in ourselves to come back from 2-1 down against a very good side and I thought we looked a good side as well.
"I think that games should be played by both sides looking to win the match, not shut up shop looking to nick it, and that is that is what we did.
The defeat hit Blackpool's hopes of reaching the play-offs and Holloway added: "The teams above us have got games in hand and realistically I think there is one place left as I think the other ones are almost nailed down.
"Cardiff are clinging onto it but any team that comes with a late run will probably have to win seven or eight of the last 10 games.
"Can we do that? Not if we let three goals in every week, but we do look like we can score so that is positive and we will be having a go for it and trying to enjoy ourselves."
Source: Team Talk
>> Terms & Conditions