chulukitabhavasindhum chittajakrodhadaitya
	pramathanapaTubuddhim shrIjagatdesikendram |
diraviDaphaNitidaksham dakshiNAshAniShaNNam
	kalashatanayamanyam manyate me manastvAm ||

Meaning:

shrIjagatdesikendram tvAm 	- O! Swami known as Pillai Lokacharyar
chulukita bhavasindhum 		- who makes the samsara ocean to be small like the little amount of water used for achamanam,
chittajakrodhadaitya pramathana
  paTubuddhim 			- who has the knowledge to kill the asura in the mind that is anger, and
dakshiNA AshAniShaNNam 		- who lives in the southern direction.
me mana: 			- My mind
manyate 			- thinks
anyam kalashatanayam 		- of you as another Agastya muni.

Vyakhyana Saram:
In this shloka, Desikan says that he considers Pillai Loakcharyar in his mind as Agastya muni.

Agastya used the ocean water as the water to perform achamanam (the water used for ritual purification). He digested and killed the asura Vatapi. He is proficient in the Tamil language (Tamil is known as Agastyam). He resides in the southern direction.

Pillai Lokacharyar reduces the samsara ocean to be the small quantity used in achamanam. He kills the terrible asura that is anger. He is proficient in the verses of Azhvars written in the Tamil language. He lives in Srirangam that is in the south.

Due to these, Desikan considers Pillai Lokacharyar to be another Agastya.