Whatever animosity remained between the Oakland Athletics and Baltimore Orioles from last month's benches-clearing incidents was hashed out on the field in the thrilling opener of this three-game series featuring first-place clubs.
Now Oakland starter Jason Hammel will look to make a statement of his own against his former club as the A's seek an eighth straight home victory Saturday night.
They each played big roles Friday in the first meeting since that series. Amid constant boos, Machado hit a go-ahead two-run homer in the seventh inning before Donaldson replied with a three-run, walkoff shot in the ninth to give Oakland (60-36) a 5-4 victory.
"Certainly there's a little irony involved in the whole thing," A's manager Bob Melvin said.
Machado, who was banned one game for taking exception to a tag by Donaldson at third base on June 6 and another four for throwing his bat two days later, says he's moved on.
"The booing is part of the game and I have to get used to it," Machado said. "You have to be able to block it out. You just try and channel your energy to do well. I have to gain everyone's respect back from everyone that I let down."
Hammel spent the previous two seasons with Baltimore and was its opening day starter in 2013 before he signed a one-year deal with the Chicago Cubs in the offseason.
Hammel (0-1, 3.60 ERA), who is 8-6 with a 3.01 ERA in 18 starts, was acquired from Chicago with Jeff Samardzija on July 5. He's made just one start with the A's, allowing three runs - two earned - in five innings of a 5-2 loss to San Francisco on July 9.
"He's got good stuff," Melvin said. "Probably not exactly what he would have hoped for, but we didn't do him any favors."
The right-hander will face the Orioles for the first time since 2008 looking to deal his former club its third loss in four games.
Baltimore (52-43) leads the New York Yankees and Toronto by four games atop the AL East after Friday's tough defeat. Jonathan Schoop also hit a two-run homer, while Machado and J.J. Hardy each finished with two hits.
The Orioles should feel confident in this contest behind Wei-Yin Chen, who is 3-0 with a 1.00 ERA and 25 strikeouts in 27 innings over four career starts against the AL West leaders.
Chen (9-3, 4.15) has won each of his last two starts, giving up two runs in six innings of a 5-2 win over Texas on July 3 before allowing three runs in 5 2-3 innings of a 4-3 win over Washington on July 10.
The left-hander is 6-1 with a 3.72 ERA over his last eight outings, including when he allowed two runs on homers to Donaldson and Derek Norris over 6 1-3 innings in Baltimore's 4-3, 11-inning loss to Oakland on June 6.
"We love what he brings to this team, we love his ... fortitude that he shows every time he goes out there and takes the ball," outfielder Adam Jones said. "We're just happy with the last three years we've had him here."
Baltimore had won seven of its previous nine on the road, but Donaldson's homer helped the A's improve to 31-15 in Oakland.