SB 8.12.36

athāvagata-māhātmya
 ātmano jagad-ātmanaḥ
aparijñeya-vīryasya
 na mene tad u hādbhutam
Synonyms: 
atha — thus; avagata — being fully convinced about; māhātmyaḥ — the greatness; ātmanaḥ — of himself; jagat-ātmanaḥ — and of the Supreme Personality of Godhead; aparijñeya-vīryasya — who has unlimited potency; na — not; mene — did consider; tat — the miraculous activities of the Supreme Personality of Godhead in bewildering him; u ha — certainly; adbhutam — as wonderful.
Translation: 
Thus Lord Śiva could understand his position and that of the Supreme Personality of Godhead, who has unlimited potencies. Having reached this understanding, he was not at all surprised by the wonderful way Lord Viṣṇu had acted upon him.
Purport: 

The Supreme Personality of Godhead is known as all-powerful because no one can excel Him in any activity. In Bhagavad-gītā (7.7) the Lord says, mattaḥ parataraṁ nānyat kiñcid asti dhanañjaya: “O conqueror of wealth, there is no truth superior to Me.” No one can equal the Lord or be greater than Him, for He is the master of everyone. As stated in Caitanya-caritāmṛta (Ādi 5.142), ekale īśvara kṛṣṇa, āra saba bhṛtya. The Supreme Personality of Godhead, Kṛṣṇa, is the only master of everyone, including even Lord Śiva, what to speak of others. Lord Śiva was already aware of the supreme power of Lord Viṣṇu, but when he was actually put into bewilderment, he felt proud to have such an exalted master.