"So he called upon his Lord: 'I am overpowered, so help me'", meaning: so take revenge for me against my people.
Muhammad said: Whoever reads "anni" (that I am) with the fatha (the short vowel 'a') on the alif - which is the most preferred recitation - the meaning is: he called out...
﴿فَدَعَا رَبَّهُ أَنِّي مَغْلُوبٌ فَانْتَصِرْ﴾ أَي: فانتقم لي من قومِي.
قَالَ محمدٌ: من قَرَأَ ﴿أَنِّي﴾ بِالْفَتْح للألف - وَهُوَ الأجود - وَالْمعْنَى: دَعَا