Eight Septuagint readings — Brenton's English Septuagint (1851) for the full text; Greek keywords as discussed by Pitre (public domain)
Genesis 3:15 — autos, 'he' shall watch for your head: the woman's seed read as an individual (p 24).
Exodus 25:5 — xyla asēpta, 'incorruptible wood' for the acacia of the Ark (pp 46, 63).
Exodus 40:35 — epeskiazen, the cloud 'overshadowed' the tabernacle: Gabriel's verb in Luke 1:35 (p 54).
2 Samuel 6 — anestē kai eporeuthē 'arose and went'; meta kraugēs 'with shouting'; treis mēnas 'three months': the Visitation's vocabulary (pp 55–56).
Isaiah 7:14 — hē parthenos, 'the virgin,' quoted in Matthew 1:23 (pp 72, 84).
2 Samuel 6:23 — heōs, 'until' the day of Michal's death: the sense of 'until' in Matthew 1:25 (p 101).
Genesis 31:37 and 1 Chronicles 23:22 — adelphoi, 'brothers,' used of cousins (pp 106–107).
Isaiah 66:7 — ōdinousa, exephygen, eteken arsen: 'in labour, escaped, bore a male' — the wording behind Revelation 12:2, 6, 5 (p 127). Genesis 35:18 — Benjamin 'son of my pain' (odynē) (p 151).
Reproduced in full. Translation: Brenton's English Septuagint (1851) for the full text; Greek keywords as discussed by Pitre (Public domain).
Why Pitre cites it
The Greek Old Testament's wording is what the New Testament writers echo; these eight places carry Pitre's arguments.