Dustin Pedroia and Mike Napoli each homered in the first to back a solid spot start from Alfredo Aceves, as the Boston Red Sox downed the Philadelphia Phillies, 9-3, in the opener of a four-game set.
Boston right-hander Clay Buchholz was slated to start Monday's opener, but was scratched due to collarbone and AC joint irritation.
Aceves (2-1) filled in admirably, allowing just one run on seven hits and three walks over six innings to help the Red Sox secure their fourth straight victory and move into sole possession of first place in the AL East.
"He took tonight as an opportunity to make an impression," Red Sox manager John Farrell said of Aceves. "He made a solid one."
Jacoby Ellsbury recorded three hits, an RBI, and a run scored, while Stephen Drew plated a pair of runs and scored twice for Boston, which will also host Tuesday's tilt before heading to Philadelphia for the final two games.
Erik Kratz smacked a solo shot and Domonic Brown added a two-run blast to account for the Phillies' offense. Starter Tyler Cloyd (1-1) was tagged for six runs on nine hits in just 2 1/3 frames to absorb the loss, Philadelphia's third in its last four games.
"Command for me, in my view, wasn't there at all tonight," Cloyd admitted. "My ball was up and I couldn't get ahead of hitters."
Ellsbury led off the game with a single and moved to third on a groundout and a wild pitch before trotting home on Pedroia's fly ball down the right-field line that snuck just inside of Pesky's Pole for a 2-0 lead.
After Cloyd fanned David Ortiz, Napoli crushed a first-pitch fastball over the Boston bullpen in right-center to make it 3-0.
The Phillies got a run back in the third on Kratz's one-out shot to right, but the Red Sox tacked on three more in the bottom half to extend their lead.
Ortiz clubbed a leadoff double before Napoli's fly ball down the right-field line one-hopped into the stands for a ground-rule double that scored Ortiz from second. Drew plated Napoli with a single to right to make it 5-1.
Cloyd then struck out Mike Carp before a Jarrod Saltalamacchia single to right ended Cloyd's night, as Michael Stutes was summoned from the bullpen.
Stutes popped out Jose Iglesias for the second out, but Ellsbury slapped a slicing fly ball into left-center field that landed just out of the reach of a diving Ben Revere.
Drew scored from second for a 6-1 lead, but Philadelphia shortstop Jimmy Rollins fired a strike to the plate to nab Saltalamacchia for the final out.
Boston padded the lead with a pair in the fifth, as Drew scorched a one-out single and Carp followed with a double to right. Saltalamacchia then ripped an RBI single to right that John Mayberry overran, allowing both runners to cross the plate for an 8-1 advantage.
Brown belted a two-run shot in the eighth to bring the visitors within five, but Mike Adams issued a bases-loaded walk to Drew in the bottom half to account for the final margin.
Boston won two of three in Philadelphia a season ago and the clubs are meeting at Fenway Park for the first time since 2010 ... Cloyd was facing an AL opponent for the first time ... Aceves last start came on April 23, when he allowed eight runs -- seven earned -- over 3 1/3 innings in a loss to Oakland ... Saltalamacchia has reached base in a career-high 16 straight games with a plate appearance.