"We didn't know what happened," Clemens said. "Everyone didn't know whether to run on the field or not."
The Astros won their season-high fifth straight by salvaging another sharp outing from Clemens, who matched his season high for strikeouts.
The Rocket allowed three runs or fewer for the 13th time in 14 starts, but walked away with a no-decision.
Brad Lidge (1-4) pitched a scoreless ninth for the win, benefiting from a game-ending play few players had ever seen before.
Willy Taveras grounded out leading off the ninth against Milwaukee reliever Jose Capellan (2-1). Lamb and Craig Biggio followed with singles to put runners at the corners, and Capellan intentionally walked Lance Berkman to load the bases.
But Miller simply stepped on the plate, apparently not realizing he needed to make a tag. Thanks to his mistake, Lamb slid home with the winning run on Huff's RBI groundout.
"I've never had a game end like that or even seen that play," Miller said.
Lamb wasn't sure if he'd scored.
"It was pretty much the oddest ending I've ever seen," he said. "I didn't know for a long time what had happened. The umpire kept signaling he was out at first, so I was thinking he would need to tag me. But I wasn't sure."
When plate umpire Rob Drake finally called Lamb safe, the Astros spilled out of the dugout to celebrate.
"Everybody was coming out, giving me high-fives," Huff said, "and I didn't know what happened. It was definitely the weirdest ending I've ever seen."
The Brewers lost their season-high sixth straight road game, wasting a strong effort from Dave Bush, who gave up two hits and struck out four in seven innings.
Before the final play, Bush matched Clemens pitch for pitch. Both breezed through the first five innings, each allowing only two hits apiece.
Clemens struck out Miller leading off the sixth, then watched Taveras sprint to catch a fly from Bush, a career .173 hitter. Clemens fanned Corey Hart for the second time in the game to end the inning.
Taveras made another great play to bail Clemens out of a bases-loaded jam in the seventh.
Cirillo led off with a bloop single to center, then went to second on Tony Graffanino's groundout.
Clemens walked Kevin Mench before Taveras dove to catch David Bell's low liner. Clemens thrust his fist in the air, then greeted Taveras with a pat on the chest as the center fielder returned to the dugout.
"I've seen it a number of times," Clemens said of Taveras. "If I get the ball up, he's going to find a way to get it."
The 26-year-old Bush didn't need any spectacular fielding to preserve his shutout bid. He retired the Astros in order for the fifth time in the seventh, striking out Huff to end his 82-pitch outing.
"Bush was outstanding," Cirillo said. "When he's dialed in, he's really good. He matched -- and even pitched better -- than Clemens."
The starters gave way to their bullpens in the eighth.
- Clemens was denied a decision for the third time in seven starts.
- Biggio's 634 doubles rank ninth on the career list, six behind Honus Wagner.
- Clemens made his 685th start, tying him with Bert Blyleven for eighth all-time.
- One night after his 30-game hitting streak ended, Taveras went 0-for-4.