Conversation so far:
Anything amazing happened during the 2009 season?
Kurt Warner announced his desire to return to the Cardinals for the 2009 season.
Did the Arizona Cardinals accept Kurt Warner?
The Cardinals offered him a two-year contract worth around $20 million but Warner was looking for a contract that would pay him about $14 million a year.
Did Kurt Warner try out for another team besides the Arizona Cardinals in 2009?
On February 27, 2009 Kurt Warner became a free agent and went on to have talks with the San Francisco 49ers.
Did Kurt Warner end up playing for the San Francsico 49ers in the 2009 season?
On March 4, Kurt Warner re-signed with the Cardinals to a two-year deal.
What are some highlights of Kurt Warner's 2009 season with the Cardinals?
On September 20, 2009, Kurt Warner broke the NFL's single-game record for completion percentage in the regular season.

Question: What did he do to break that record?
Self-contained rewrite: What did Kurt Warner do to break become?