Next opponent – Arizona Diamondbacks
Last game: Nationals 8, Diamondbacks 4
| Opponent | Won | Lost | Year |
| ARI | 4 | 2 | 2005 |
| ARI | 5 | 1 | 2006 |
| ARI | 1 | 6 | 2007 |
| ARI | 2 | 4 | 2008 |
| ARI | 5 | 1 | 2009 |
| ARI | 4 | 3 | 2010 |
| ARI | 3 | 5 | 2011 |
| ARI | 4 | 2 | 2012 |
| ARI | 3 | 1 | 2013 |
| Year | Won | Lost |
| 2005 | 81 | 81 |
| 2006 | 71 | 91 |
| 2007 | 73 | 89 |
| 2008 | 59 | 102 |
| 2009 | 59 | 103 |
| 2010 | 69 | 93 |
| 2011 | 80 | 81 |
| 2012 | 98 | 64 |
| 2013 | 85 | 75 |
| Grand Total | 675 | 779 |
| 2005-2013 | Won | Lost | 2011-2013 | Won | Lost | 2012-2013 | Won | Lost | 2013 | Won | Lost |
| NYM | 82 | 82 | NYM | 36 | 19 | NYM | 26 | 11 | MIA | 14 | 5 |
| ATL | 79 | 85 | PHI | 30 | 25 | MIA | 23 | 14 | NYM | 12 | 7 |
| MIA | 70 | 92 | MIA | 30 | 25 | PHI | 20 | 17 | PHI | 11 | 8 |
| PHI | 69 | 96 | ATL | 25 | 30 | ATL | 16 | 21 | ATL | 6 | 13 |
| CHC | 31 | 28 | CHC | 14 | 7 | CHC | 10 | 4 | SDP | 5 | 2 |
| PIT | 31 | 28 | MIL | 12 | 9 | MIL | 9 | 6 | CHC | 4 | 3 |
| ARI | 31 | 25 | SFG | 12 | 7 | CIN | 9 | 5 | MIL | 4 | 3 |
| HOU | 30 | 26 | SDP | 12 | 7 | SDP | 8 | 4 | CIN | 4 | 3 |
| MIL | 30 | 33 | CIN | 11 | 9 | SFG | 8 | 4 | COL | 4 | 3 |
| CIN | 29 | 31 | COL | 10 | 11 | COL | 7 | 7 | SFG | 3 | 3 |
| SFG | 28 | 29 | ARI | 10 | 8 | ARI | 7 | 3 | CHW | 3 | 0 |
| STL | 23 | 34 | HOU | 10 | 4 | HOU | 7 | 1 | PIT | 3 | 4 |
| COL | 23 | 40 | PIT | 9 | 11 | PIT | 5 | 7 | ARI | 3 | 1 |
| SDP | 22 | 33 | STL | 8 | 11 | STL | 4 | 9 | DET | 2 | 2 |
| BAL | 20 | 26 | BAL | 6 | 10 | CHW | 3 | 0 | MIN | 2 | 1 |
| LAD | 20 | 33 | CHW | 5 | 1 | TOR | 3 | 0 | KCR | 2 | 1 |
| SEA | 9 | 0 | LAD | 5 | 13 | BOS | 3 | 0 | LAD | 1 | 5 |
| TOR | 9 | 9 | BOS | 3 | 0 | BAL | 3 | 7 | BAL | 1 | 3 |
| CHW | 5 | 4 | TOR | 3 | 0 | LAD | 3 | 9 | CLE | 1 | 2 |
| MIN | 4 | 5 | SEA | 3 | 0 | DET | 2 | 2 | STL | 0 | 6 |
| KCR | 4 | 2 | TBR | 2 | 1 | TBR | 2 | 1 | Grand Total | 85 | 75 |
| TBR | 4 | 5 | KCR | 2 | 1 | KCR | 2 | 1 | |||
| BOS | 4 | 5 | DET | 2 | 2 | MIN | 2 | 1 | |||
| CLE | 4 | 5 | MIN | 2 | 1 | CLE | 1 | 2 | |||
| NYY | 4 | 5 | CLE | 1 | 2 | NYY | 0 | 3 | |||
| LAA | 3 | 6 | NYY | 0 | 3 | Grand Total | 183 | 139 | |||
| OAK | 3 | 0 | LAA | 0 | 3 | ||||||
| TEX | 2 | 4 | Grand Total | 263 | 220 | ||||||
| DET | 2 | 8 | |||||||||
| Grand Total | 675 | 779 |
