Oakland, CA -- Mark Mulder tossed eight strong innings to lead the Oakland Athletics to a 13-3 win over Pittsburgh and a three-game series sweep at the Coliseum.

Mulder (8-2), who has not lost since April 28, earned his sixth straight win by limiting the Pirates to three runs on four hits while striking out seven. He also lowered his earned run average to 2.97.

Adam Melhuse blasted a grand slam and drove in five runs for the Athletics, who ran their win streak to a season-high eight games. Scott Hatteberg and Eric Byrnes each blasted a homer and drove in three runs in the winning effort.

"[Oakland] is one hot club," Pittsburgh manager Lloyd McClendon said.

Craig Wilson and Daryle Ward each smacked solo homers for the Pirates, who have dropped eight straight and 13 of the last 14.

Pirates starter Kip Wells (3-5) absorbed the loss after allowing eight runs on 11 hits in just 4 1/3 innings of work.

"We are on such a bad streak," Pittsburgh outfielder Rob Mackowiak said. "We have not done anything well on this road trip."

The Athletics snapped a 3-3 tie in the fifth by sending 11 hitters to the plate and scoring six runs to take a 9-3 lead. Mark Kotsay, Jermaine Dye and Hatteberg led off the frame with consecutive singles, with Hatteberg's driving in Kotsay for the first run.

Erubiel Durazo followed with a single to load the bases and Melhuse cleared them with a grand slam to make it 8-3. Reliever John Grabow couldn't escape the inning before allowing an RBI single to Kotsay to cap the rally.

Oakland tacked on three runs in the following frame, courtesy of Hatteberg's solo homer and Byrnes' two-run single, to make it 12-3.

Eric Karros capped the scoring with an RBI single in the eighth.

"When guys are getting all those hits," Melhuse said, "you want to get one, too."

Oakland pushed a run across in the second. Durazo led off with a double and went to third on Bobby Crosby's fly out to right. Melhuse followed and reached on a Jose Castillo fielding error, which allowed Durazo to come home.

The Athletics loaded the bases with nobody out in the third, but they could only score once, courtesy of Hatteberg's RBI sacrifice fly.

The Pirates tied the game in the fourth on Jason Bay's RBI groundout and Wilson blasting a solo homer over the wall in left field.

Byrnes answered with a solo homer of his own in the home half of the frame to put Oakland back up by a score of 3-2.

Ward led off the fifth by smacking a solo homer to tie the game at 3-3.

Game Notes:

The Athletics also swept the Pirates in a three-game set at PNC Park during the 2002 season...Mulder improved to 2-0 in his career against Pittsburgh...Oakland improved to 23-10 at home this season...Wells fell to 0-3 in his career versus the Athletics...Oakland has scored a major league-leading 95 runs in June. The A's have scored 79 of those in the last seven contests...Hatteberg ran his hitting streak to a career-high 14 games...Melhuse's grand slam was the A's third in the last six games...The Pirates losing streak is the longest since the 2000 season.