Veteran Blues striker Phillips made the most of being handed his first league start of the campaign in Saturday's 2-1 victory over Bolton at St Andrew's by opening the scoring in the fourth minute.
The 37-year-old latched on to Sebastian Larsson's corner and unleashed an effort that Wanderers goalkeeper Jussi Jaaskelainen could not stop going in.
Phillips had also netted when Birmingham hosted Bolton in the FA Cup quarter-final three weeks earlier after being named in the first XI and he now has four goals in four starts in all competitions this term.
Asked about the former England frontman, McLeish said: "We did speak in January about more minutes for him and maybe I can look back and say 'could I have used him more in the first half of the season?'
"We did it for the right reasons - maybe I could have. But he's a just a genius in the box.
"I've kept saying, even since the start of the season, that in terms of technique he is still the top forward at the club.
"You just wonder about the legs but he has shown that it wasn't a problem.
"He scored the goal, he brought people into play, he held the ball up and despite not being the biggest guy in the world, he annoys centre-halves and they never get free headers."
Phillips, who might have left Birmingham in January, could now be set for a key role in the Blues' run-in having produced what McLeish described as a "brilliant" performance.
"There were a few Championship clubs interested in him and indeed, even a link with a Premier League club," McLeish said.
"But what can I say? He has looked fantastic over the last few weeks and he has deserved to be involved for the next game.
"We've got to consider Kevin in that kind of form in every game."
Birmingham, looking keen to make amends for the 3-2 defeat they suffered in the cup game, went 2-0 up yesterday just before the hour mark when Craig Gardner crashed a shot in off the post.
Johan Elmander's volleyed reply for Bolton with 20 minutes remaining set up a tense finale, but the hosts hung on for three vital points.
The win initially catapulted McLeish's team, who had gone in to the contest lying 19th, up five places in a congested bottom half of the table, although Blackburn's goalless draw with Arsenal in the late kick-off meant the Blues finished the day in 15th.
The midlands outfit have put a two-point gap between themselves and the drop zone with eight games to play and McLeish knows his team are embroiled in an epic battle for survival.
"I never said when we were 12th or whatever that we were safe and no team can say that, up to about 11th position," he said.
"We've only been looking at our own position in terms of what we need to do, but certainly this will give us a lot of confidence."
The victory was Birmingham's first of any kind since their Carling Cup triumph at Wembley in February and Bolton manager Owen Coyle has stressed that his players must not be distracted by the prospect of their FA Cup semi-final at the same venue a fortnight today.
"Birmingham were obviously desperate for the three points, as we were because we want to continue our progress," Coyle said.
"People had alluded to the fact that we have the semi-final coming up, but I have said to the players that having worked hard for nine-and-a-half or 10 months up to this point, we want to make sure we have a big finish to the season.
"To do that we have to perform well.
"We had some big players missing, but the lads that came in showed what they are all about, and we probably do feel hard done by to be leaving with nothing.
"That is the margins in the Premier League, though, and you cannot be giving teams a two-goal head start.
"For all your quality and what you have at your disposal it is a big ask to come back from that, although we very nearly did it."
