Jon Lester was highly critical of himself after allowing 10 earned runs against the Oakland Athletics on Tuesday.

The left-hander called himself the "weakest link" in the Chicago Cubs' rotation.

"I feel like they had a better plan than I did," Lester said of the Oakland Athletics hitters. "Plain and simple. They executed their plan and before we could make the adjustment there's eight runs up there."

The A's sent 12 batters to the plate during an eight-run second inning, then plated three more in the fourth on a Stephen Piscotty home run.

"What happened is I gave up 11 runs, so it doesn't matter how I feel," Lester said. "Doesn't matter about a game plan, doesn't matter about executing pitches, doesn't matter about anything. I gave up 11 runs, so it really doesn't matter."