Aluko's opener came at the end of a concerted period of Aberdeen pressure
Dunfermline forced a Homecoming Scottish Cup replay with a late equaliser against Aberdeen.
Graham Bayne came close for the home side before Charlie Mulgrew's powerful free-kick for the Dons was tipped over by goalkeeper Paul Gallacher.
Sone Aluko gave the visitors a deserved lead after 61 minutes with a well-struck shot from the edge of the area.
But Nicky Phinn scrambled home a leveller eight minutes from the end to earn the First Division side a draw.
Neither side were able to carve out clear-cut scoring chances in the opening stages with Phinn volleying over from a Stephen Glass corner.
Finalists in 2004 and 2007, Dunfermline almost broke the deadlock on 26 minutes when Jamie Mole's cross was headed narrowly wide by Bayne.
At the other end, Aluko retrieved a bouncing ball in the box and saw his downward volley blocked by Pars captain Scott Wilson's clearance.
Aluko then won Aberdeen a free-kick almost 30 yards from goal which gave Mulgrew the chance to test former Scotland keeper Gallacher.
The Aberdeen full-back whipped a curling effort towards the top corner and Gallacher got a strong hand behind the ball to tip it over.
The pace and trickery of Aluko continued to cause Dunfermline problems at the start of the second half with the Englishman creating space on the edge of the area before having his shot blocked by Greg Shields.
Aberdeen kept the pressure up and Wilson made another vital interception as Jamie Smith forced his way into the penalty area.
Phinn ensured Dunfermline got a replay with his late strike
A combination of Bayne and Wilson did enough to put off Tommy Wright as he tamely headed Smith's cross into the arms of Gallacher.
But Dunfermline were unable to prevent Aberdeen taking the lead as Aluko received Derek Young's pass on the left and slammed a low shot into the far corner of the net.
Phinn almost levelled for the home side when he arrived late in the box to head another Glass corner towards goal but the alert Jamie Langfield turned the effort wide.
Andy Kirk, who had replaced the injured Bayne, was next to threaten the Aberdeen goal, Langfield beating away the striker's powerful drive.
Moments later, Scott Muirhead volleyed straight at Langfield from a promising position.
The Pars's pressure eventually yielded a reward when Mole's shot was saved by Langfield and, after Zander Diamond had prevented Kirk converting the rebound, Phinn forced the ball into the net from close range.
The Dons went back on the offensive and Lee Mair's volley was deflected over by Wilson.
And a draw was confirmed in injury time when substitute Richard Foster flashed an effort wide of the Dunfermline goal.
The two sides will meet again on Tuesday 17 March at Pittodrie.
Dunfermline manager Jim McIntyre:
"Aberdeen started the second half like a train and they really had us under the cosh and deservedly took the lead.
"We had to change things about a wee bit. We changed system and we got the break.
"But I thought we deserved to equalise and I thought we had the better chances in the first half.
"I've got to give special mention for Nicky Phinn. He's going to be a real prospect. That's nine goals from midfield this year and there's not many midfielders who have that.
"It's advantage Aberdeen (in the replay), they're the Premier League side but it's up to us to go and put on the performance we put on today.
"Hopefully we can just improve our end product a wee bit and that'll be good enough."
Aberdeen manager Jimmy Calderwood:
"In the first 20 minutes they played really well. We came out the traps quite slowly and I was really annoyed.
"After the first 20-25 minutes, I thought we dominated with Jamie Smith and Sone Aluko wide.
"In the second half, we came out and played at pace and got it from side to side and looked much more comfortable.
"We went ahead and it looked as if we would cruise it.
"We let it slip. They got their break. It was poor defending from us and Jamie Langfield's not too happy with himself either.
"All in all, I suppose a draw was a fair result. Hopefully we can go and finish it at Pittodrie."
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