Jansen came on in the ninth to protect a one-run lead for Kenta Maeda, who won his first Major League matchup with countryman Shohei Ohtani but didn't win the game. Jansen got Justin Upton and Albert Pujols for two quick outs and had Ohtani 0-2, with the radar gun lighting up in the mid-90s.
What could go wrong?
For one thing, Jansen threw four high cutters and walked Ohtani, who was 0-for-3 on the night as a designated hitter.
"Unacceptable," said Jansen. "0-2, had him where I wanted to. Feel like I lost my feel. That walk irritated me, but I've got to keep my composure."
Jansen didn't keep Ohtani close and he took off for second base. Catcher Yasmani Grandal double clutched, then sailed his throw into center field. Ohtani took third on the error and scored the tying run on David Fletcher's single.
"I tried to be quick, but I have to make sure I make a quality pitch or I leave something in the middle," said Jansen.
On a check swing, Ian Kinsler sent a blooper down the right-field line. Yasiel Puig charged, hesitated, let it drop and tried to barehand the one-hopper, but bobbled it as Fletcher went to third. Puig then overthrew the cutoff man, and his one-hop throw kangarooed over Grandal. The ball went to the screen because Jansen wasn't backing up the plate, and Fletcher scored the walk-off run.
"Not a good play all the way around," said Roberts.
"This game is on me today," said Jansen, who suffered his third blown save, but first since April 27. "I take all the blame. I've got to be backing up home plate. I saw the guy stop at third. I kind of stopped with him instead of keep going. I take this loss, all the blame on me."
Well, not quite. The explosive Dodgers offense was held to four hits by starter Felix Pena and four Angels relievers, with Matt Kemp's two RBI singles the only Dodgers damage done.
"There were just some things we didn't do well," said Roberts. "To lose a game, to give it away in the ninth like we did, we haven't lost a game like this in quite some time. Kenta, [Scott] Alexander, [Daniel] Hudson all threw well, and to get your closer in the game, one strike away from winning a baseball game and to lose a baseball game, it's tough."
Especially tough for Maeda, who struck out nine in 5 2/3 innings and whose only run allowed scored on a balk, when Kinsler deked him with a fake steal and Maeda was called for a quick pitch.
In his last three starts, Maeda has 27 strikeouts in 19 2/3 innings while allowing only three earned runs. He struck out Ohtani and retired him on a soft popup, downplaying the achievement afterward, despite becoming almost an afterthought since the sensational arrival of Ohtani this season.
"It's not really about motivation," Maeda said of facing his countryman. "But I'm sure the Japanese fans are excited to see this kind of a matchup."
MOMENT THAT MATTERED On Kemp's sixth-inning RBI single, which came with one out after walks to Justin Turner and Cody Bellinger, the latter was called out for running out of the baseline trying to avoid a tag in a rundown on a wild play in which Kemp reached second only to find it occupied by Bellinger, then retreated to first. The Dodgers had three walks and a single that inning but scored only one run. More >
SOUND SMART The temperature at first pitch, 108 degrees, was an Angels record. By the ninth inning, temperatures plunged to a refreshing 92. More >
YOU GOTTA SEE THIS The Dodgers are 41-2 in games they've led after eight innings.
HE SAID IT "It's a little weird. Baseball can be a little freaky." -- Kemp, on the ninth-inning turnaround
UP NEXT Ross Stripling has a chance to bolster his All-Star credentials when he starts against the Angels and former Dodgers Minor Leaguer Deck McGuire in Saturday's 4:15 p.m. PT game. Stripling's last win was June 15, four starts ago. Justin Turner will serve as the designated hitter.
Ken Gurnick has covered the Dodgers for MLB.com since 2001.