Rizzo homered and had his first four-hit night Friday in the Cubs' wild 8-7 win over the Mets as Travis Wood earned his fourth straight victory.
"We'll get him through it," Dempster said.
The Cubs leaned on Rizzo and Reed Johnson, who led off the game with a homer and matched Rizzo with four hits, the seventh time he has done so in his career. They had a season-high 18 hits and won for the eighth time in 11 games, but not before a hairy ninth inning that saw Carlos Marmol nearly blow a four-run lead.
"The ninth inning was exciting," Rizzo said. "But it sure was good to win."
With an 8-4 lead in the ninth, Marmol gave up a solo home run to Jordany Valdespin, walked the bases loaded and gave up a two-run single to Ike Davis to make it a one-run game. Manager Dale Sveum already had used Shawn Camp and James Russell and had Chris Volstad warming up in the bullpen in case of emergency.
"If they tied it, he was out," Sveum said. "(Manny) Corpas was down with back spasms, so it would've been Volstad."
But Marmol induced Lucas Duda to hit a liner back to him, and he threw to Rizzo for the game-ending double play.
Wood was watching the ending in the clubhouse.
"It was getting interesting, but he pulled it off," Wood said. "He's a good pitcher and he made the play and got the double play."
Wood improved to 4-3, allowing two earned runs over six innings despite not having his best stuff. His ERA over his last four starts is 1.01, and he has been the team's hottest pitcher in Dempster's absence.
"I've been throwing the ball well, and as a team we've been playing pretty good baseball," Wood said.
The Cubs jumped on Mets veteran Johan Santana, who tied a career high by giving up 13 hits, including homers to Johnson, Rizzo and Jeff Baker. Rizzo's three-run homer off Santana in the five-run fifth broke the game open.
The Cubs are trying to close out a poor first half on a high note, hoping to build on this stretch in the second half.
"It's kind of a simple formula," Dempster said. "If you execute pitches better, have better at-bats and play better defense, you're going to get better results. And we've been doing that more consistently, getting some really good starting pitching and timely hits.
"Rizzo has done a great job and kind of brought in that new energy. So just try and build off that and have a winning road trip."