The 36-year-old rattled in 33 goals in his five years with the Phoenix, and still looked to have plenty of life left in his legs when he came off the bench for the last 20 minutes of yesterday's match at Forsyth Barr Stadium.
With the match tied at 1-1, Ifill ran on to a perfect pass from Fabien Kurimata to set up a one-on-one opportunity with Southern United goalkeeper Tom Batty.
Batty had kept his side in the match with a string of brilliant saves earlier in the match, but Ifill fired past him with a superb finish to put his team 2-1 up.
The home side had a chance to snatch a draw just four minutes later, when Sam French was brought down inside the box by Hawkes Bay defender Finlay Milne.
He received a straight red card for the foul, but Harley Rodeka's well-struck spot kick was saved by a diving Josh Hill, who guessed correctly to his right.
‘‘I'm gutted,'' Southern United coach Mike Fridge said after the match.
‘‘It's a very, very hard one to take, this one. There is a lot of ifs and buts.
‘‘At the end of the day, you have got to give the goalie credit. But it was a great opportunity for us to take away a point.''
It looked as if debutant striker Lewis Jackson had salvaged the home side a draw 15 minutes from time, when he knotted the game up at 1-1 with a superb finish.
Jackson, the brother of former Southern United captain Tom Jackson, scored just 14 minutes, after replacing Regan Coldicott.
He scored eight goals for the youth team last year, and his first for the seniors was a brilliant effort into the top-left corner from near the edge of the box.
Southern United had been chasing an equaliser since the visiting team hit the front through Sam Mason-Smith in the dying minutes of the first half.
He found the back of the net after banging in a rebound off Batty's gloves from one of three corner kicks late in the first half.
Like most of Southern United's games this season, the team has hung tough in the first half but conceded just before the break.
‘‘We gave them a real good game,'' Fridge said.
‘‘We had a go at them; we played some nice football. But again, we let in a very cheap goal two minutes before halftime.
‘‘I'm gutted for the boys. They put so much work into it. It just shows, when you're down at the bottom you don't get any luck.''
In addition to Batty having a fine game in goal, defender Jude Fitzpatrick was outstanding at the back and twice made scrambling blocks in the box.
Captain Seamus Ryder had a busy first half down the left-hand flank. He almost set up the opener in the 21st minute, when a nice ball was headed down by Coldicott, but French's left-footed effort went just wide.
It was part of a 15-minute spell which Southern United dominated, and resembled a similar patch in the second half.
Moments before Jackson's equaliser, Rodeka made a sparkling run down the right-hand side, jostling past his marker to fire a pinpoint cross into the box. But Coldicott's scuffed shot was saved to deny the home side.
Southern United has now scored just six goals to the 22 it has conceded from its nine matches, and is dead last in the ASB Premiership with three points.
Its next game is against Waitakere United in Auckland next Sunday.
Southern v Hawkes Bay
The scores
Hawkes Bay United 2
Sam Mason-Smith 43, Paul Ifill 83
Southern United 1
Lewis Jackson 75
Halftime: 1-0
