Eng. +ing after to?

In English, there are common phrases called idiomatic expressions 慣用語, which have specific meaning and fixed format that you can't change. There are also fixed combination of words that people commonly use to convey a meaning, such as afraid of something, in front of something, accustomed to something, look forward to something,etc.

(1) (be) second (only) to something : therefore you have to put a noun or noun phrase after the phrase "second to"; and, keeping is a gerund acting as a noun in the noun phrase "keeping control of the ball".

(2) barrier to something : same reason as above.

(3) fail to do something : fail + to-infinitive + object of verbal

(4) hear somebody/something do something : hear + object of hear + bare-infinitive + object of verbal

"I hate hearing her say such thing."
- "hearing (gerund) her say such thing" is a noun phrase acting as object of the main verb "hate".
- you cannot use "she" after "hearing" as "she" can't be used as an object in any case.
- "say" is a bare-infinitive relating the the object "her"
- "such thing" is the object of "say".