-1 ap as my ability power as support mordekaiser [gameplay]

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1928849903/39629195?tab=overview

i was playing a team builder match as support Mordekaiser. was looking at my stats and noticed a -1 for my ability power. Im curious to know how my ability power was in the negatives and if it had any effect on the damage that i was dealing. my runes were armor quins, mana regen marks, scaling health seals, and magic resist glyph. my masteries and items can be seen in the player build page linked above.