"I knew it felt good, but I couldn't assume anything," Sanchez told the Associated Press. "I think it's the first time since junior college I hit a walk-off homer.
"I didn't look at it as a 13-game losing streak ? I looked at it as 13 games we wanted to win and we weren't winning, and we needed to find a way to win.
"You hope you never see anything like that happen to us again. Now we're looking forward to starting to win some games. Let's do something and turn it around and hope it's over."
He also leads the National League in hitting. Sanchez is batting .363 and Nomar Garciaparra of the Dodgers is batting .362.
The 28-year-old Sanchez, who is an infielder, has hit five home runs to go along with 41 runs batted in. He also notched a run-scoring double in the sixth to give Pittsburgh a 6-4 lead and matched his career high for hits in a game.
Sanchez, who was acquired from the Boston Red Sox in 2003 after being originally drafted by the Atlanta Braves in 1996, is 28 for 64 during the stretch. He batted .291 last season, his first full season in the majors.
The Pirates, who were winless for more than two weeks, broke the modern-era (since 1900) club record of 12 straight losses set in 1939 on Wednesday. The only longer losing streak in Pittsburgh's major league history was a 23-game slide by the Alleghenies in 1890.
Until the current streak, the Pirates (27-53) had not lost more than 10 in a row in 38 years.
Pittsburgh had last won when it recorded a 9-7 victory against the St. Louis Cardinals on June 14.
Zika's no-hitter
lifts team to title
Muir-Chase Plumbing Coach Jim Mulligan thought he jinxed it.