Romero replaced starter Brett Myers after Aramis Ramirez's RBI single put runners on first and second. He struck out pinch-hitters Reed Johnson and Ronny Cedeno before walking Kosuke Fukudome to load the bases. He then got a called third strike past rookie Geovany Soto to end the inning, and was visibly delighted after the big performance.
"It's one of those situations where you're trying to do your best and you come in against a lot of good hitters," Romero said. "It's nothing to disrespect the opponent, it's just the fact that you get into a situation that you want to do your best and on top of that I got one of my hometown friends, Geovany Soto."
Werth homered twice and Ryan Howard connected for his major league-leading 37th homer as the Phils ended a three-game skid in which they couldn't protect a lead.
Brad Lidge pitched a perfect ninth for his 32nd save in as many chances.
"I had a huge at-bat there in the eighth inning and didn't come through," Soto said, adding he wasn't bothered by Romero's display. Both are from the San Juan, Puerto Rico, area.
"It means I'm a big hitter," Soto said. "It's part of the game. Sometimes you hit a big homer and you kind of stand there and look and enjoy the success at that moment. I think it was a big strikeout for him."
Werth, who missed all of 2006 after wrist surgery, also hit a tiebreaking two-run single in the sixth for the Phillies.
"I've had a tough career," he said. "I had a good year, get hurt, then have a bad year, then don't play one year, then turn into a platoon, kind of a bench player all of a sudden. Hopefully this sets me back in the right direction."
Howard and Werth connected against Neal Cotts in the eighth to make it 5-1 and then Romero cut off the Cubs' rally.
"We just squandered too many opportunities and left a lot of people on base," manager Lou Piniella said after his team lost for just the 20th time in 71 home games. "You can't do it every day."
Myers (8-10) allowed 11 hits and two runs in seven-plus innings with no walks and eight strikeouts. He is 5-1 in eight starts since being recalled from the minors on July 20.
The 6-foot-4 right-hander didn't given up a run in his two previous starts and had his scoreless inning streak snapped at 17 when the Cubs got three straight singles from Mark DeRosa, Fukudome (a bunt) and Soto with one out in the second to take a 1-0 lead.
Ted Lilly (13-8) retired 12 straight before Werth led off the fifth with his 19th homer. Lilly lost another matchup with Werth in the sixth, surrendering a two-out single that scored Chase Utley easily and Howard on a nice slide around Soto.
Home plate umpire Chris Guccione, who was in the middle of a disputed call at first Friday, was involved in another in the fourth inning Saturday when the Cubs had runners at the corners. When Howard picked up Lilly's bunt down the first-base line and tried to tag him, Guccione initially ruled Lilly safe at first.
After Howard protested, crew chief and first base umpire Tim Welke met with Guccione and ruled Lilly was out -- even though replays were inconclusive on whether Howard tagged him.
Lilly said he didn't feel a tag and didn't see one on the replay, either.
"The home plate umpire said that he wasn't tagged. The first base umpire said he was tagged in the hip," Piniella said. "One of them was right and one of them was wrong."
On Saturday, Guccione had called Howard out at first on a close play with runners also on the corners. Replays showed he beat the throw and if he'd been ruled safe, the Phils would have taken a seventh-inning lead in a game they eventually lost 3-2.
- Werth is 9-for-17 with three homers and seven RBI against the Cubs this season.
- Myers is 2-7 on the road this season.
- Ramirez's RBI single gave him 100 RBI for the sixth time.