SAN FRANCISCO — For the three innings on Friday night, the Giants were back to playing their April brand of baseball.

They stole bases. They stacked extra-base hits. They cashed in with runners in scoring position. All the things they did during the season’s first full month.

The next six innings, by contrast, were emblematic of the baseball they’ve played over the last two months. They wasted numerous opportunities to keep taking on runs, and by night’s end, they have lost 7-6 to the Tampa Bay Rays.

Their losing streak has hit six games. They’re 59-63 on the season. And they’ve now lost 14 of their last 15 games at home, something that hasn’t been done since 1901.

Right-hander Landen Roupp pitched three-plus innings in his first start back from the injured list, allowing five earned runs and striking out five batters.

The first four innings were a true see-saw battle.

The Giants took a 1-0 lead in the bottom of the first on Dominic Smith’s RBI single to score Adames, but the Rays tied things up at one in the top of the second on Junior Caminero’s solo homer.

San Francisco re-took the lead in the bottom of the second on a pair of RBI doubles from Christian Koss and Heliot Ramos, but Tampa Bay again responded by tying the game on a sacrifice fly from Brandon Lowe and an RBI single from Yandy Díaz.

The Giants created a 6-3 lead in the bottom of the third on a solo homer by Adames, his 19th home run of the season, and a two-run double by Patrick Bailey. The Rays, again, had their response, plating three runs and knocking Roupp out of the game in the process.

Through four innings, both teams had plated six runs. That remained the score until the bottom of the eight.

Casey Schmitt, already filling in at third for the injured Matt Chapman, led off the inning by getting plunked on his right shoulder, instantly going down in pain and collapsing to the ground. Manager Bob Melvin removed Schmitt from the game in favor of Tyler Fitzgerald, giving the Giants elite speed on the bases.

Jung Hoo Lee followed up Schmitt’s plunking with a single, then Christian Koss loaded the bases by also getting hit after trying to lay down a sacrifice bunt. That set up no outs with the bases loaded, a golden opportunity to scratch across the go-ahead run.

The Giants would not score.

Bailey smashed a 99.6 mph line drive that was caught by shortstop Ha-Seong Kim. Drew Gilbert couldn’t plate a run either, hitting a grounder to first baseman Bob Seymour that was thrown home for the force out. With two outs, Heliot Ramos hit into an inning-ending force out, and the opportunity was squandered.

The Rays, by contrast, wouldn’t waste their opportunity in the top of the ninth. All-Star Randy Rodríguez allowed a run in his first pitching appearance since August 6, giving the Rays a 7-6 lead.

Rafael Devers set the table to tie the game in the bottom of the ninth with a leadoff double, just barely beating the throw to second. The Giants, again, would squander the opportunity.

Meeting of the Seymours

According to Baseball Reference, there have only been five players in major-league history with the last name “Seymour.” Three of those five — the Giants’ Carson Seymour and the Rays’ Ian Seymour and Bob Seymour — happened to play in Friday night’s game.

Not only are all three rookies, but Friday was Bob Seymour’s debut. Appropriately enough, Carson Seymour faced Bob Seymour, a first baseman, in the top of the sixth inning. After going hitless in his first two at-bats, Bob Seymour reached base for the first time as a big leaguer by drawing a walk.

Ian Seymour allowed two runs over 3 1/3 innings of relief with four strikeouts.