Cole scored in each half – the first a penalty – with Chris Long wrapping things up against a Livi side whose lone strike came from Jack Fitzwater, meaning ninth placed ’Well move onto 35 points from 32 games which is nine points clear of second bottom Hamilton and 10 ahead of bottom club Kilmarnock.
Alexander said: "I don’t think there is a secret (with Devante’s good form). Look, he’s a good player.
"He’s a good striker. I think we’ve got other good strikers and other good players in the squad but – I think I said yesterday – we always have a way of treating people, that’s across the board.
"And I think he’s responded well to it. I don’t know how he’s been treated in the past, I can’t really put my finger on it.
"But we ask him to play in good areas and we try to feed these lads because we know they’re goalscorers. Chris Long’s got a fantastic goal as well today, Jordan (Roberts) scored last week and was such a threat.
"So we know we’ve got good talented players but we try to keep round pegs in round holes and I think Coley’s an out and out striker.
“I thought we started the game in a real good tempo, pinned Livi in for long periods of the game and deservedly took the lead.
"They had a good spell just before half-time when they were sniffing an equaliser and it was a good warning for us going into half-time that the game wasn’t dead.
"We scored the second goal, unfortunately conceded quite soon after to make it difficult for ourselves but I thought we gradually gained control again and once we got the third I thought we were reasonably safe but it was only because of the way we approached the game. I’m delighted for the players."
Motherwell, who will finish in the bottom six this season after being third last term, have no fixture this weekend and will next return to Scottish Premiership action at Kilmarnock on Saturday, March 20, kick-off 3pm.