Chacon is tied with Los Angeles’ Kevin Brown with 10 wins, but Brown failed in his bid on Sunday in a 6-3 loss to Anaheim.
Besides taking over the NL lead in wins, Chacon can join Toronto’s Roy Halladay as the majors’ only pitchers with 11 victories.
Chacon has won six of his last seven starts, giving up two earned runs or fewer five times. He held the Padres to two earned runs and five hits over 6 2-3 innings in a 5-3 win on Wednesday.
Chacon, 25, became the fastest Rockies pitcher to reach 10 wins and just the second to get that many before the All-Star break.
“I’d lie if I said my confidence hadn’t gone up, because it has,” said the third-year hurler, who won a combined 11 games in his first two major league seasons. “I would never have thought I’d be 10-3 right now.
“I just want to ride it out as long as possible.”
The Rockies took two of three from Detroit with Sunday’s 5-3 home victory.
Helton is batting .516 (16-for-31) during an eight-game hitting streak with a homer, five doubles, a triple and five RBIs. Walker has four RBIs and three doubles over his last nine games, batting .414 (12-for-29) over that span.
The Padres come in after winning their first series since April 23-24, taking two of three from the major league-leading Seattle Mariners with Sunday’s 3-1 home victory.
San Diego, which has baseball’s second-worst record, has won five of its last eight.
“We’ve been playing better baseball and we knew we had our work cut out for us against the best team in baseball this week,” said center fielder Mark Kotsay, who has six RBIs in his last 10 games.
“This club doesn’t give up. It doesn’t want to be embarrassed.”
STANDINGS: Rockies - 4th place, 6 1/2 GB, NL West. Padres - 5th place, 20 1/2 GB, NL West.
ROCKIES PROBABLE STARTER: Chacon (10-3, 4.10 ERA). Chacon is 2-1 lifetime against the Padres with a 3.47 ERA in six starts.
PADRES PROBABLE STARTER: Kevin Jarvis (0-1, 6.30 ERA). Jarvis loss to Chacon and the Rockies on Wednesday, allowing five earned runs and nine hits in five innings. The outing marked his second start since coming off the 60-day disabled list, where he was recovering from an elbow injury. The right-hander is 3-4 lifetime against the Rockies with a 6.45 ERA in 12 games, including eight starts.
OFFENSIVE LEADERS: Rockies - Helton, .344 avg. and 65 runs; Preston Wilson, 17 HRs, 66 RBIs and 6 SBs. Padres - Mark Loretta, .307 avg.; Ryan Klesko, 14 HRs and 42 RBIs; Xavier Nady, 34 runs; Ramon Vazquez and Shane Victorino, 7 SBs.
SEASON SERIES: Rockies, 6-4.
STREAKS AND NOTES: Rockies - Kevin Ritz also had 10 wins for Colorado before the All-Star break, doing so in 1996. … The Rockies finished their interleague schedule a franchise-best 9-6. They were 9-7 in 1997. … OF Jay Payton is batting .333 (14-for-42) during a 10-game hitting streak. … LHP Brian Fuentes has stranded 20 of the last 23 baserunners he has inherited. Padres - 3B Sean Burroughs sat out Sunday with a tweaked groin muscle. 1B Dave Hansen started in his place, going 1-for-3 with an RBI. … Despite batting just .143 (2-for-14) against RHP Chacon, 1B Klesko has homered and driven in four runs. … San Diego has issued an NL-high 311 walks.
ROAD/HOME RECORDS: Rockies - 10-25 on the road; Padres - 14-25 at home.
INJURIES: Rockies - INF Ronnie Belliard (ankle), 15-day DL; OF Chris Richard (shoulder), 60-day DL; RHP Denny Stark (side), 60-day DL. Padres - INF Lou Merloni (knee), 15-day DL; SS Vazquez (abdomen), 15-day DL; OF Jason Bay (wrist), 15-day DL; RHP Clay Condrey (oblique), 15-day DL; RHP Trevor Hoffman (shoulder), 60-day DL; 3B Phil Nevin (shoulder), 60-day DL.