WHAT IT MEANS: Jon Niese tossed 7 1/3 scoreless innings and Ike Davis delivered a tiebreaking two-run homer in the seventh against Edwin Jackson as the Mets beat the Nationals, 2-0, Saturday night in D.C.

Frank Francisco, twice pulled from games in the past week in the ninth inning, notched his 20^th save -- aided by a solid catch from Mike Baxter at the wall in the right-field corner to retire Ryan Zimmerman for the first out.

Jackson had allowed only one hit -- Baxter’s one-out triple in the first -- before walking David Wright to open the seventh. He then served up the two-run, opposite-field homer to Davis with the next pitch. The Nats starter struck out 11, matching teammate Stephen Strasburg’s July 25 total for the most by a major league pitcher against the Mets this season. The Mets K'd 15 times in the game, matching their season high.

Terry Collins removed Niese with the southpaw’s pitch count at 109 -- 13 shy of matching his career high -- after a leadoff flyout by Bryce Harper in the bottom of the eighth.

Niese has now tossed a career-high 13 1/3 consecutive scoreless innings.

Jon Rauch recorded the final two outs of the eighth. He has now allowed only one earned run in 15 innings spanning 21 appearances since June 28. Still, Niese's removal arguably appeared quick since he is due to pitch with an extra day of rest Friday against the Astros at Citi Field.

WHAT’S NEXT: The Mets begin implementing their six-man rotation, with Jeremy Hefner (2-4, 4.76 ERA) starting Sunday’s 1:35 p.m. series finale opposite Nats left-hander Gio Gonzalez (15-6, 3.29). Hefner’s wife Sarah then is expected to have labor induced and give birth before his next start.