TORONTO -- The Boston Red Sox have had a sensational start to the season and the Toronto Blue Jays, slow starters in recent seasons, have had a better than expected beginning.

When the two American League East leaders open a three-game series Tuesday night at the Rogers Centre, however, both teams will be coming off their first series losses of the season after dropping their past two games.

The Red Sox (17-4) lost twice in a row to the Athletics in Oakland, including a no-hitter on Saturday, and a 4-1 decision Sunday. They had been averaging 6.5 runs in their first 19 games.

"You never want long losing streaks," Red Sox first baseman Mitch Moreland said. "This team is capable of anything. We had two games where we had good pitching against us. That's going to happen.

"But we have a great offense and great pitching. This is a very good team, so I think we're going to be able to limit that long-term damage where you lose a lot of games."

Red Sox manager Alex Cora said, "We think we have a great offensive club, but this is going to happen. We're not going to score seven, eight runs a night."

The Blue Jays (13-8) lost the final two games of a four-game series against the Yankees on Saturday and Sunday in New York to go 1-3 in the set.

The Blue Jays lost 5-1 Sunday, held to three hits in seven innings by Yankees starter Luis Severino.

"We did have some opportunities, not so much (Sunday), but the first three games," Blue Jays manager John Gibbons said.

"You know, we've been (playing) really well, really well lately," said Toronto left-hander Jaime Garcia, who took the loss Sunday. "The guys are swinging really amazing, the bullpen has been unbelievable and we as starting pitchers, we feel like we're going to take off.

"We believe in ourselves. We just got stay focused on the process, continue to compete, continue to give us a chance to win and in the long term, things will go that way."

Right-hander Rick Porcello (4-0, 1.40 ERA) will start Tuesday for Boston. Left-hander J.A. Happ (3-1, 4.50 ERA) will go for Toronto.

Porcello has pitched a total of 13 innings without giving up a run in his past two starts and has won all four of his outings this season.

In 21 career outings (20 starts) against the Blue Jays, he is 9-9 with a 4.98 ERA. He has two or fewer earned runs in each of his past three starts at the Rogers Centre. In 11 career games (10 starts) at Rogers Centre, he is 4-6 with a 4.99 ERA.

Happ is 7-3 with a 3.22 ERA in 17 career outings (16 starts) against the Red Sox.

The Blue Jays were 0-for-9 with runners in scoring position Sunday in New York with their only run coming on a home run by Teoscar Hernandez.

Seven of the outfielder's 12 hits this season have gone for extra bases (three doubles, one triple and three home runs).

The Blue Jays reached 13 wins this season in 19 games after needing 34 games to win their 13th last season. They need one more win to guarantee that they will finish at .500 or better for March-April.

During the previous five seasons, Toronto had the worst March-April record in the majors, going 52-75 (.409).

In winning 17 of their first 20 games entering Sunday, the Red Sox matched the franchise's best start through 20 games. The 1946 Red Sox also won 17 of their first 20 on the way to a 21-3 start. The Red Sox were the first team to win 17 of their first 20 games since the 2003 Yankees (17-3) and 1987 Milwaukee Brewers (18-2).

The Red Sox believe that they're equipped to avoid long losing streaks.

"With our pitching staff, that's the case," Cora said. "Offensively, we feel capable of scoring runs every night. We're capable of scoring a lot. We're not going to score seven or eight every night, but this offense is going to be fine. We're going to hit. We still have had a good road trip, 4-2. We need to go to Toronto and win the series."