Lake makes a splash for Cubs
Junior Lake homered and also scored a career-high six runs to help the Chicago Cubs record a 17-5 victory over the St Louis Cardinals.
Rookie Mike Olt, Emilio Bonifacio, Anthony Rizzo and Starlin Castro provided good support for Lake as the Cubs scored 17 runs in St Louis for the first time since 1974.
There were also plenty of runs at Yankee Stadium where the visiting Mets claimed derby honours over the New York Yankees with a 9-7 victory.
The Yankees led 4-1 early on, but the Mets fought back and, following Chris Young's go-ahead two-run shot in the eighth, they recorded their fifth straight win over the Bombers.
The good news for the Yankees is that American League east rivals Baltimore were unable to move any further clear at the top of the division as they slumped to a 4-1 defeat to Detroit.
AL west leaders the Oakland Athletics powered on, though, as they made it five wins on the trot - the hottest streak in the MLB - with a 5-4 win over the Chicago White Sox.
The White Sox trailed by four runs heading into the ninth, but, despite getting back to within touching distance, they could not draw level as Oakland improved to 24-15 for the campaign - their best record at this stage of a season in 24 years.
Seattle are Chicago's nearest challengers following their 12-5 win over Tampa Bay, a victory all but secured after the opening three innings where they Mariners established an 9-0 lead, with the third-placed Los Angeles Angels slipping further back after going down 7-3 at the Toronto Blue Jays.
In the National League, west leaders San Francisco recorded a 4-2 win over the Atlanta Braves, with Tyler Colvin smashing his first hit as a Giant into McCovey Cove. The victory was San Francisco's 14th in their last 18 games.
Elsewhere, Miami slumped to their fourth successive loss after going down 6-5 to the LA Dodgers,
the Texas Rangers continued their recent domination of rivals the Houston Astros with a 4-0 win, while the Washington Nationals ended a three-match losing streak with a 6-5 triumph over the Arizona Diamondbacks.