Eoin Griffin, who scored a late try in that game, is restored to the outside centre role, alongside Nevin Spence who shifts across from the right wing.
The fit-again Darren Hudson comes in as the second change to the back-line, donning the number 14 jersey. Brendan Macken and Noel Reid drop to the replacements bench.
With Rhys Ruddock unavailable, Belfast Harlequins and Ulster's Niall Annett will captain the side from hooker.
Ben Marshall has been preferred to Brian Hayes in the second row, and Jordi Murphy, the Ireland Under-19 skipper, takes over from Ruddock as blindside flanker. Corinthians and Connacht prop Denis Buckley has been added to the bench.
Clarke's youngsters are hoping to chalk up their first pool win and qualify for the 5th-8th place play-offs. Like Ireland, Argentina lost their opening two matches to England (48-22) and France (31-23).
Previewing Sunday's game, the Irish coach said: "We were disappointed with our accuracy (against England). We were getting into good areas of the field, but forcing passes - passes that weren't calculated and as a result of that we've been coughing up possession easily.
"We weren't maintaining pressure on the opposition so that's a big focus for us.
"Our set piece was good again, our scrum was good, our lineout was very good and we were able to disrupt some of their platform.
"But it's really about backing ourselves now and putting all the facets of the game together. We've refocused our goals, we're aiming to be in the second-tier competition and playing for fifth in the world."
The Argentina v Ireland clash will be broadcast live on Setanta Sports Ireland and Sky Sports 1 (Interactive). There will also be a live stream of the game on the tournament website.
IRELAND UNDER-20 Team & Replacements (v Argentina U-20s, IRB Junior World Championship, Estadio El Coloso del Parque, Rosario, Sunday, June 13, kick-off 4.10pm local time/8.10pm Irish time):
15 - Andrew Conway (Blackrock College/Leinster)
14 - Darren Hudson (St. Mary's College/Leinster)
13 - Eoin Griffin (Corinthians/Connacht)
12 - Nevin Spence (Ballynahinch/Ulster)
11 - Simon Zebo (Cork Constitution/Munster)
10 - James McKinney (Queen's University/Ulster)
9 - John Cooney (UCD/Leinster)
1 - Jack O'Connell (Lansdowne/Leinster)
2 - Niall Annett (Belfast Harlequins/Ulster) (capt)
3 - Stewart Maguire (Old Belvedere/Leinster)
4 - David O'Callaghan (UCC/Munster)
5 - Ben Marshall (UCD/Leinster)
6 - Jordi Murphy (Blackrock College/Leinster)
7 - Dominic Ryan (Lansdowne/Leinster)
8 - Patrick Butler (Shannon/Munster)
16 - David Doyle (UCD/Leinster)
17 - Denis Buckley (Corinthians/Connacht)
18 - Brian Hayes (Cork Constitution/Munster)
19 - Brian O'Hara (UL Bohemians/Munster)
20 - Michael Heaney (Belfast Harlequins/Ulster)
21 - Noel Reid (UCD/Leinster)
22 - Brendan Macken (Blackrock College/Leinster)
IRELAND'S POOL B RESULTS/FIXTURES:
Saturday, June 5: Ireland 22 France 25, Estadio El Coloso del Parque, Rosario
Wednesday, June 9: Ireland 21 England 36, Estadio El Coloso del Parque, Rosario
Sunday, June 13: Argentina v Ireland, Estadio El Coloso del Parque, Rosario, 4.10pm local time (8.10pm Irish time)