Argentina arrive as defending champions with a 3-0-0 World Cup group record, 7-1 goal difference and an attack generating roughly 1.8 xG per game, while Algeria scraped through at 1-1-1 with a negative goal difference and under 1.0 xG per match. Expect Argentina’s 4-3-3/4-2-3-1 possession structure (Messi and Nico Paz between lines, Lautaro Martínez as a high xG penalty-box striker) against Algeria’s compact 4-3-3/4-1-4-1 mid-block built around Aouar and Gouiri linking transitions and Mahrez as the primary chance creator. The decisive duel is Messi (already on 4 World Cup 2026 goals with ~0.9 non-pen xG + xA per 90, plus a hat-trick in the earlier 3-0 win vs Algeria) attacking the right half-space versus Algeria’s left side, where Mahrez offers 0.35 xA/90 but limited defensive output, and Aïssa Mandi must cope with Lautaro’s box movement (career club rate ~0.55 goals + 0.65 xG/90 over the last two seasons). Secondary swing matchups include Nico Paz’s progressive passing and late box entries against Aouar (who averaged ~0.25 non-pen xG + 0.20 xA/90 in qualifying but only around 1.2 tackles + interceptions/90), and Argentina’s set-piece unit (centre-backs combining for 6+ headed goals across qualifying) attacking Algeria’s defence that conceded over 25% of its qualifying goals from dead balls. Argentina’s pressing, with a PPDA in the 8–9 range in qualifying and group play, should force low-percentage long balls to Gouiri (qualifying: ~0.40 goals + 0.45 xG/90 but under 0.10 xA/90), meaning Algeria’s upset path is heavily skewed toward high-variance events: winning set-piece margins, Mahrez producing >0.5 expected assists on counters, and keeping Argentina’s non-pen xG under 1.2 despite a historical H2H that now reads 3-0 to Argentina with a 6-0 aggregate score. Statistically, Argentina’s superior shot quality (roughly +0.20 xG/shot vs Algeria), defensive record (multiple clean sheets, 0 shots on target conceded in the first 3-0 meeting), and attacking depth make the 67% no-vig win probability consistent with underlying metrics unless Algeria dramatically outperforms its usual finishing and xG allowed.