Two teams residing in treasured playoff positions go head-to-head Friday night when the San Francisco Giants visit the cross-bay rival Oakland Athletics to kick off a three-game interleague series.

The Giants (25-24) put their head above .500 with a come-from-behind, 6-4 win over the Seattle Mariners on Thursday afternoon, a victory after which San Francisco walked off the field in first place in the National League wild-card race.

The Giants find themselves in a mad scramble with Philadelphia, Cincinnati, St. Louis, Milwaukee, Colorado and the New York Mets to finish with one of the two best records among the third- and fourth-place teams this season.

It's a bit of a surprise San Francisco is in the position it's in. Shortly after taking two gut-wrenching defeats and one humiliating setback in a three-game home sweep at the hands of the A's in mid-August, the Giants began a 17-8 surge that offset an 8-16 start.

San Francisco copied some of the Athletics' late-game magic in rallying Thursday. Offensive hero Wilmer Flores gladly credited the victory to the Giants' bullpen, which threw seven innings of three-hit, shutout ball after starter Tyler Anderson was ejected in the third inning with his team trailing 4-1.

"One thing about us is: Any inning, we can score runs," Flores said after the game. "We trust our bullpen keeping us right there. If not for the bullpen today, I don't think we could have won it."

With the relief corps having thrown 5 1/3 innings of shutout ball as well in a Wednesday win over the Mariners, the Giants could use a strong effort from Friday starter Logan Webb (2-3, 4.96 ERA). The right-hander has been moved up in the rotation after Trevor Cahill was summoned for bullpen duties on Wednesday.

Webb, 23, went four effective innings in a 3-1 loss at San Diego in the second game of a doubleheader Sunday. He was the starter when the A's teed off on a demoralized Giants club in a 15-3 shellacking five weeks ago.

Webb allowed three runs in 4 1/3 innings that day, a no-decision that left him with an 0-1 record and 7.00 ERA in two career starts against the A's.

Oakland (31-19) has a chance to clinch the American League West this weekend, but the A's have other fish to fry. They are currently dueling the Chicago White Sox and the Tampa Bay Rays for the best record in the AL heading into the postseason.

The A's were in better shape at 28-15 a week ago but have since lost four of seven, limited to a total of 11 runs in the defeats.

Oakland will show its rival a bit of a different look in the rematch series, with Jake Lamb having been signed to replace injured third baseman Matt Chapman.

"Jake's been big for us," manager Bob Melvin said Wednesday after watching Lamb improve to 5-for-11 in his first three games for Oakland. "You get inspired coming to a different team and want to put a good showing early on in a completely different situation. It makes you feel like part of the group that much quicker when you contribute right away."

The Giants are plenty familiar with Lamb, who last played for the Arizona Diamondbacks.

The A's are scheduled to send right-hander Chris Bassitt (4-2, 2.92 ERA) to the mound in the series opener. The 31-year-old is 0-1 in his career against the Giants in two starts despite a 3.09 ERA.