"The neroazzurri are built to reach a place among the top three. They have invested a lot and they are a renowned club," Inzaghi said at a news conference on Tuesday.
"They have lost ground due to some injuries, but they are finding continuity with Pioli. They are one of our rivals for Europe."
Lazio are fourth with 34 points, eight off the pace set by Juventus, one behind AS Roma and level with Napoli, while Inter are seventh with 27.
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Inzaghi was the Lazio youth team coach when he took charge of the seniors after Pioli quit in April following a 4-1 defeat by bitter rivals Roma seven matches before the end of the championship.
"It will be my pleasure to see Pioli and (Antonio) Candreva again," Inzaghi said.
Italy winger Candreva joined Inter last summer after four and a half years at Lazio and has made seven league appearances this season, scoring three goals.
"I had an excellent relationship with Candreva, in the last seven games of last season he was always available a gave me a lot," said Inzaghi.
Pioli, who replaced the sacked Frank de Boer last month and has led Inter to three wins in his five matches in charge, also told a news conference the match at San Siro will be important for Inter.
"(Lazio) will be tricky opposition for all the sides looking to qualify for the Champions League. They'll be able to prepare well for every game given that they're not in Europe this year," Pioli said.
Lazio missed out on Europe after finishing eighth in Serie A last season.
Inter were fourth last season, qualifying for the Europa League, but they are also out of Europe now having finished bottom of their group.
(Reporting by Silvia Recchimuzzi in Gdynia; Editing by Rex Gowar)
