| Clue | Source | Date |
|---|---|---|
| Battle in a brain game | Universal | 26 Jun 2020 |
| Challenge intellectually | Newsday | 17 Jun 2016 |
| Intellectually compete against | Wall Street Journal | 25 Jan 2016 |
| Challenge intellectually | ||
| Test one's intellectual mettle against | ||
| Test one's intellectual mettle |