Race Comment Explainer

Original comment with matches highlighted:

led, ridden before 2 out where headed, lost 2nd approaching last, kept on one pace run-in

Matched phrases & meanings

Phrase	Meaning
kept on one pace run-in	The horse maintained its existing speed through the final run to the finish line, but could not accelerate or quicken relative to the leader.
ridden before	The jockey started urging the horse aggressively before the second-last obstacle to try and get it back into contention.

Summary

The horse maintained its existing speed through the final run to the finish line, but could not accelerate or quicken relative to the leader.
The jockey started urging the horse aggressively before the second-last obstacle to try and get it back into contention.