Conversation so far:
What was the biggest race Affirmed won in 1977?
In the Hopeful Stakes, Affirmed pulled away in the final sixteenth of a mile to win by half a length.
What was Affirmed's time in the 1977 Hopeful Stakes?
Affirmed's time of 1:152⁄5 for 6 1⁄2 furlongs was a new stakes record.
How fast did Affirmed run at the Belmont Park?
Where did Affirmed race after the Belmont?
Affirmed followed Belmont up with a win in the Youthful Stakes on June 15 where he defeated Alydar by eight lengths.

Question: Was Alydar his biggest rival?
Self-contained rewrite: Was Alydar Affirmed's biggest rival?