Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Date | Tournament | Surface | Opponent in the final | Score |
| --- | --- | --- | --- | --- |
| 15 August 2004 | Islamabad | Clay | Toshiaki Sakai | 7–6(3) 7–6(5) |
| 22 August 2004 | Lahore | Grass | Toshiaki Sakai | 1–6 6–4 6–3 |
| 5 September 2004 | Karachi | Hard | Tommaso Sanna | 6–3 6–4 |
| 12 September 2004 | Hyderabad | Hard | Tai-Wei Liu | 6–7(5) 6–1 6–1 |
| 20 August 2006 | Delhi | Hard | Ravishankar Pathanjali | 7–6(7) 6–4 |
| 12 August 2007 | Ludhiana | Hard | Aditya Madkekar | 6–3 7–6(5) |
| 29 October 2007 | Lahore | Grass | Divij Sharan | 4–6 6–3 6–4 |
Question:
On what date did the opponent in the Toshiaki Sakai final play on a grass surface?
Answer:
22 August 2004