RICHMOND, Va. – The Portland offense finally awoke after a lengthy slumber on its southern swing, but the Sea Dogs still couldn’t avoid a series sweep at the hands of the Richmond Flying Squirrels, falling 6-5 in 10 innings Thursday night.

Javier Herrera’s one-out single drove in Ryan Lollis with the winning run and handed the Sea Dogs their third straight loss. Portland had managed only two runs in the first two games of the series.

The start of the game was delayed two hours and 10 minutes because of a late-afternoon rainstorm that left several large pools of water in the outfield and created considerable doubt whether the series finale would be played.

Richmond scored first when the San Francisco Giants’ farmhands strung together three singles in the second off starter Keith Couch. Tyler LaTorre’s grounder through the hole into left with two outs plated the run.

Couch, making his 10th start after beginning the season as a reliever, ran into trouble again in the fifth. With one out, Kelby Tomlinson singled to center, stole second and went to third on a groundout.

Joe Panik made it 2-0 with a double down the left-field line that eluded the dive of third baseman Michael Almanzar. Following a walk, Mark Minicozzi doubled past Almanzar’s backhand attempt to score Panik.

Couch, who came into the game with an 8-3 record (5-1 as a starter), hit Angel Villalona to load the bases but escaped further damage by inducing a fielder’s-choice grounder.

The Sea Dogs got one back in the sixth. Shannon Wilkerson led off with a single and scampered to third on a wild pitch on ball four to Garin Cecchini. Almanzar then hit what appeared to be an inning-ending, double-play bouncer to short but Tomlinson bobbled it and was only able to get one out, allowing Wilkerson to score.

In the bottom of the inning, Adam Duvall homered to left off Couch to put Richmond ahead 4-1. It was Duvall’s third homer of the series.

Portland answered with four runs in the seventh. Matt Spring led off with a homer (No. 10) to left, followed by back-to-back singles by J.C. Linares and Ryan Dent. Wilkerson sacrificed the runners, and Linares scored when Minicozzi threw away his bunt.

Derrick Gibson was intentionally walked to load the bases, before Almanzar’s two-run single gave Portland the lead, 5-4. Richmond tied it in the eighth on a two-out single by Minicozzi after a catcher’s interference put runners on first and second.

NOTES: Left-hander Henry Owens, who had been dominating the High-A Carolina League (123 strikeouts in 104 2/3 innings) at Salem, was promoted to Portland on Thursday and is expected to make his Double-A debut on Saturday vs. Bowie. Owens, 21, the No. 5 prospect in the Boston organization according to Baseball America, was 8-5 with a 2.92 ERA in 20 starts with Salem. …

To make room for Owens on the roster, righty Mike McCarthy (1-3) was assigned to Salem. …

Despite a 1-3 record in July, right-hander Matt Barnes registered a 1.74 ERA in five starts, including Wednesday’s no-decision against the Squirrels.