PHILADELPHIA — Taijuan Walker entered Monday having not allowed a run in his first 10 2/3 innings of the season, an impressive start for someone who struggled as much as he did a season ago.

Walker wasn’t dominant in his first two starts. He danced with fire at times. He didn’t get burned. But the veteran right-hander continued to get in trouble on Monday in a four-game series opener against the Giants at Citizens Bank Park. And, this time, he got scorched, leading to an eventual 10-4 Phillies loss.

Walker started his night with 1 1/3 innings of scoreless baseball. But after Matt Chapman grounded out to start the second inning, five straight Giants hitters turned into five straight Giants runs.

After Chapman’s groundout, Heliot Ramos started San Francisco’s barrage with a double to right field. Two batters later, Ramos scored on a Wilmer Flores single.

With batters now on first and second, Walker got Patrick Bailey to poke a ball that didn’t leave the infield grass. Walker bounced off the mound, toward first base. He gloved the ball. He fired, across his body, to second. It was an aggressive play. It didn’t pay off. The ball sailed into center field. LaMonte Wade Jr. scored. Everyone was safe.

Had Walker gone to first for the easy out, he would’ve found himself in a bit of an easier situation — two runners on with two outs. Instead, a run scored, and now a pair of runners were on with just one out.

Two pitches later, Walker hung a cutter to nine-hole hitter Tyler Fitzgerald. The Giants’ second baseman accordingly hit a three-run shot to left field, giving San Francisco a 5-3 lead.

Two batters later, Willy Adames hit a solo homer, making it a 6-3 ballgame.

The six-run top of the second came to an end one batter later. Walker left the field to a spattering of boos. He battled through three more innings, not allowing a run or a runner to reach second base. But the damage was done.

The lineup, shut out in two of three games over the weekend in St. Louis, spotted Walker three runs in the bottom of the first. They scored on a Trea Turner double, Nick Castellanos single and thanks to Max Kepler beating out a potential double-play ball with the bases loaded.

Later on, the Phillies (9-7) had a few chances to get back into the game, but nothing came of them.

One of their better shots was in the bottom of the seventh, down 8-4. With two runners on, two outs and J.T. Realmuto at the plate, the Phillies catcher pulled a ball down the left-field line. He stood and watched as the ball floated and landed to the left of the foul pole for a long foul ball. Three pitches later, in a 3-2 count, Realmuto was called out on strikes on a more than questionable call by home plate umpire Tony Randazzo.

With their loss, the Phillies are now 2-5 since taking two of three of the mighty Los Angeles Dodgers.