PHILADELPHIA (Interstat) — The Washington Nationals erupted for four runs in the first inning and never looked back, routing the Philadelphia Phillies 13-2 on Monday night at Citizens Bank Park in a lopsided result that defied pregame projections.

A crowd of 35,609 watched as the Nationals battered Phillies starter Taijuan Walker early and often, amassing 17 hits while Washington starter Foster Griffin and two relievers combined to stifle a Philadelphia lineup that managed just seven hits.

The victory improved Washington’s early season record to 3-1, while the Phillies fell to 1-3.

The most important part of the game was its immediate and decisive beginning. The Nationals sent nine men to the plate in a relentless top of the first inning, seizing control before the Phillies ever took a swing. James Wood worked a leadoff walk and Luis García Jr. followed with a ground-rule double. After a groundout, Daylen Lile’s fielder’s choice brought Wood home. CJ Abrams then singled to score García, and after a Drew Millas single loaded the bases, José Tena lined a single to center to plate Lile. Jorbit Vivas capped the outburst with a sacrifice fly to score Abrams, staking Griffin to a 4-0 lead before he threw a pitch.

Washington added a single run in the second on a strange force-out play that allowed Brady House to score, and two more in the third, one on a fielder’s choice by García and another on a force-out by House, extending the lead to 7-0.

Griffin, the winning pitcher, was effective in his five innings of work. He allowed five hits and two earned runs, both coming on a two-run homer by Phillies catcher Rafael Marchán in the fifth inning that briefly cut the deficit to 7-2. Griffin struck out five and walked none, earning his first win of the season.

Walker took the loss for Philadelphia, surrendering seven runs, all earned, on 10 hits over five innings. He fell to 0-1.

The Nationals bullpen sealed the victory with four scoreless innings. Brad Lord was particularly sharp, allowing just one hit over three frames with three strikeouts. Cole Henry worked a perfect ninth to close out the game.

After the Phillies’ only scoring in the fifth, Washington answered with two runs in the sixth. Lile led off with a double, advanced to third on an error, and scored on a single by Tena. Tena later scored on a caught stealing play that involved a rundown, pushing the lead to 9-2.

The Nationals put the game completely out of reach with a four-run ninth inning against reliever Jonathan Bowlan. The rally featured a bases-loaded walk by Wood, a two-run single by García, and a force-out by Lile that brought in another run.

García finished 2 for 6 with three RBIs. Tena went 3 for 5 with two RBIs, and Lile was 2 for 6 with two RBIs. For the Phillies, Marchán’s two-run homer accounted for all of their offense.

The result was a stark contrast to pregame expectations. Statistical models had projected a close Nationals win, while betting markets heavily favored the Phillies, installing them as a 1.5-run favorite with an implied win probability over 70 percent. The combined 15 runs sailed over the projected total of 9.

The Nationals entered the game having taken two of three from the Chicago Cubs over the weekend. The Phillies, meanwhile, were coming off a series loss to the Texas Rangers where they dropped two of three.

The two teams will continue their series on Tuesday and Wednesday in Philadelphia before both embark on different paths. Washington will host the Los Angeles Dodgers for three games beginning Friday, followed by a series against the St. Louis Cardinals. The Phillies will head west for a six-game road trip, starting with three against the Colorado Rockies in Denver and three against the San Francisco Giants.