Matsyapurana 171.22

171.22

tapasā tejasā caiva varcasā niyamena ca
sadṛśīmātmano devīṃ samarthāṃ lokasarjane //

She, by virtue of Her austerities, equalled Brahmâ and was gifted with the faculty of the creation of the universe Brahmâ thus engaged in creation, first created the three-footed Gâyatrî, adored by the Vedas and then the Prajâpatis and the oceans.—22 23.