Race Comment Explainer

Original comment with matches highlighted:

tracked leaders, d before last 3 out, before last

Matched phrases & meanings

Phrase	Meaning
Tracked leader	Followed closely behind the leaders.
ridden before	The jockey started urging the horse aggressively before the second-last obstacle to try and get it back into contention.
Weakened	The horse lost speed and dropped back through the field.

Summary

Followed closely behind the leaders.
The jockey started urging the horse aggressively before the second-last obstacle to try and get it back into contention.
The horse lost speed and dropped back through the field.