WHAT IT MEANS: R.A. Dickey wishes it was still June.

Since the calendar turned to July, the 37-year-old knuckleballer has given up 21 runs (19 earned) on 39 hits in 26 1/3 innings, which amounts to an ERA of 6.49.

On Tuesday night, he suffered his first -- and only other -- loss since April 18. He had won 11 straight decisions -- the third-longest streak in franchise history.

Dickey’s line: 6 IP, 8 H, 5 R (4 ER), 1 BB, 7 SO

The Mets (47-50), who fell, 5-2, to the Nationals at Citi Field, have lost five in a row, 11 of their last 12 and are 1-10 since the All-Star break.

Dickey (13-2) cruised through the first three innings before allowing a two-out RBI double to Danny Espinosa in the fourth. He pitched a 1-2-3 fifth, then got two quick outs before imploding in the sixth.

He gave up five straight two-out hits in the frame -- including a two-run bomb to Adam LaRoche which ended up in the second deck in right field.

RECORD TIME: Jordany Valdespin did it again. Valdespin hit his MLB-leading fifth pinch-hit homer of the season leading off the eighth. His five pinch-hit homers are the most in a single season for any batter in franchise history.

FINALLY: Ronny Cedeno gave the Mets a 1-0 lead -- their first lead in a game since Thursday -- with a two-out, RBI single down the first-base line in the second. It didn’t last. It was also the lone blemish on Gio Gonzalez’s ledger. The left-hander went seven innings and allowed just that run on two hits to improve to 13-5.

CLOWN HITTING BRO: Teenage phenom Bryce Harper went 0-for-4 with three strikeouts. He walked in the ninth, but was caught stealing afterward.

FINE RETURN: Manny Acosta threw a scoreless seventh after being promoted from Triple-A.

UP NEXT: Jeremy Hefner (1-3, 5.85 ERA) vs. Stephen Strasburg (10-4, 2.85) on Wednesday in a rare 12:10 p.m. start.