On April 16th the Red Sox stood at 2-10, from April 16 - August 26 the Red Sox compiled a record of 78-40 (the best record in MLB in that period) & were coming of a 3 game sweep @ Texas in which they outscored the Rangers 30-7. The Red Sox had an overall record of 80-50 (on pace to win 99 games) & were 1 game up on NY ( at this point they were 10-2 against NY) for the AL East lead & 9.5 games up on TB in the division.
From August 27 - Sept 28 the Red Sox went 10-22, losing 4 out of 6 to NY, 6 out of 7 to TB, & 5 out of 7 to Baltimore. The Sox won back to back games once (August 27th a day night doubleheader against the A's.), yet the Houston Astros won back to back games 4 different times in that same span.
The suppose "Aceses" for the Red Sox (Beckett & Lester) went a combined 4-8 & Jonathan Papelbon compiled 2 saves in that time period. In the month of September alone the Red Sox went 7-20.
As a team the Red Sox finished 1st in Runs Scored (875), 2nd in Batting Average (.280), 1st in On Base Percentage (.349), & 1st in Slugging Percentage (.641). As for pitching the Sox finished 22nd in ERA (4.20), 9th in Batting Average Against (.247), 16th in WHIP (1.31), & 26th in quality starts.
The $140 million dollar man Carl Crawford finished with a line of .255/.289/.405/.694 with 11 HR's, 56 RBI, 23 BB's, 104 SO's, & 18 SB's.
Folks, that is how you choke up a 9.5 game lead in the Wild Card in the last month of the season.