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 | Opponent | Score | Loss | Attendance | Record |
| --- | --- | --- | --- | --- | --- |
| April 4 | @ Philadelphia Phillies | 4-8 | Hernández (0-1) | 44080.0 | 0-1 |
| April 6 | @ Philadelphia Phillies | 7-3 | Worrell (0-1) | 23435.0 | 1-1 |
| April 7 | @ Philadelphia Phillies | 5-4 (10) | Cormier (0-1) | 21693.0 | 2-1 |
| April 8 | @ Florida Marlins | 0-9 | Ohka (0-1) | 19327.0 | 2-2 |
| April 9 | @ Florida Marlins | 3-2 (10) | Alfonseca (0-1) | 30739.0 | 3-2 |
| April 10 | @ Florida Marlins | 0-8 | Patterson (0-1) | 25089.0 | 3-3 |
| April 11 | @ Atlanta Braves | 2-11 | Day (0-1) | 16584.0 | 3-4 |
| April 12 | @ Atlanta Braves | 4-3 | Kolb (0-1) | 20122.0 | 4-4 |
| April 13 | @ Atlanta Braves | 11-4 | Thomson (1-1) | 19093.0 | 5-4 |
| April 14 | Arizona Diamondbacks | 5-3 | Vázquez (0-2) | 45596.0 | 6-4 |
| April 16 | Arizona Diamondbacks | 9-3 | Ortiz (1-1) | 34943.0 | 7-4 |
| April 17 | Arizona Diamondbacks | 7-3 | Koplove (1-1) | 35463.0 | 8-4 |
| April 18 | Florida Marlins | 4-9 | Ohka (1-2) | 24003.0 | 8-5 |
| April 19 | Florida Marlins | 3-6 | Hernández (1-2) | 25990.0 | 8-6 |
| April 20 | Atlanta Braves | 2-0 | Ramírez (1-1) | 27374.0 | 9-6 |
| April 21 | Atlanta Braves | 1-2 | Cordero (2-1) | 30728.0 | 9-7 |
| April 22 | @ New York Mets | 1-3 | Loaiza (0-1) | 28488.0 | 9-8 |
| April 23 | @ New York Mets | 5-10 | Ohka (1-3) | 44058.0 | 9-9 |
| April 24 | @ New York Mets | 11-4 | Zambrano (1-2) | 43313.0 | 10-9 |
| April 25 | Philadelphia Phillies | 4-5 | Day (1-2) | 24956.0 | 10-10 |
| April 26 | Philadelphia Phillies | 3-1 | Lieber (4-1) | 23332.0 | 11-10 |
| April 27 | Philadelphia Phillies | 0-3 | Loaiza (0-2) | 27483.0 | 11-11 |
| April 29 | New York Mets | 5-1 | Seo (1-1) | 30627.0 | 12-11 |
| April 30 | New York Mets | 5-3 | Zambrano (1-3) | 40913.0 | 13-11 |
Question:
Who was the opponent when the Washington Nationals had a record of 8-4?
Answer:
Arizona Diamondbacks