Here is the data i have gathered from the Natal Charts of the teams.
NOTES:
Charts at the bottom of this post.
It is truly unknown what aspects influence Victory for a team, therefore assumptions are made that conjunctions are good, square/oppostions are bad if there is too many of them.
Some of the information provided may be inaccurate, use with care!
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Chelsea FC (playing in Blue/White)
It seems Chelsea's birth is more known, 10th March 1905,
https://en.wikipedia.org/wiki/Chelsea_F.C.
transit Uranus on natal Jupiter
transit Uranus on natal Venus
transit Uranus trine natal Uranus
transit Mercury on natal Moon
transit Saturn trine natal Moon
transit Moon square natal Jupiter
Mars/Jupiter Midpoint at 11 Aqua (Mercury in Taurus at 10 degree, square)
Jupiter/Pluto Midpoint at 25 Taurus (Sun at 28 Taurus)
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Man Utd (playing in Red/White)
Date of birth (27th October 1883) taken from their first possible fixture, it is unknown if this is true, reference
https://en.wikipedia.org/wiki/1883%E2%80%9384_Newton_Heath_LYR_F.C._season
tVenus trine nSun
tPluto square nMercury
tJupiter conjunct nVenus
tMars opp nJupiter
tMoon sextile nUranus
tNN conjunct nMars
tSun conjunct Pluto
tMoon on nVictory
Mars/Jupiter Midpoint at 4 Leo
Jupiter/Pluto Midpoint at 2 Cancer (Chiron at 1 Aries)
Uranus will soon square both Man Utd's Sun, Mars and Jupiter, but it is too far away.
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Verdict
Uranus is aspecting both Jupiter and Venus of Chelsea.
Therefore, Chelsea have the advantage on this basis.