A party seeking to vacate an arbitration award must file a petition to vacate or a response (to a petition to confirm) seeking vacation of the award within the shorter of 10 days after service of the petition to confirm or 100 days after service of the arbitration award.  (CCP 1288.2, 1290.6.)  Here, even though defendant filed a response to the petition to confirm less than 10 days after it was served, the response was filed more than 100 days after service of the arbitration award.  So, it was late and thus conferred no jurisdiction on the trial court to vacate the award.  It had to confirm the award instead.