John Lackey went toe-to-toe with the Angels’ best, and he proved himself once again. Lackey twirled seven impressive innings Sunday, yet two mistakes were all that the Angels needed to earn a victory, as Jered Weaver and Co. shut out the Red Sox, 3-0, in the series’ rubber match. It was a frustrating night for the Red Sox’ offense, but it was especially maddening because it spoiled another solid effort from Lackey. Lackey wasn’t one of the three Red Sox players named to the American League All-Star Team on Saturday, but you could argue that he’s been one of Boston’s most valuable players this season. Beyond Clay Buchholz — whose injury has limited his ceiling so far — Lackey has undoubtedly been the Red Sox’ most consistent pitcher. We haven’t come to the All-Star break just yet, but the sample size is growing. Lackey has now made 15 starts, and his ERA sits at an impressive 2.80. He has surrendered three earned runs or fewer in 13 of his 15 starts, and nine of his last 10 outings have resulted in a quality start. This isn’t to say that Lackey should have been given strong All-Star consideration, as there were other AL starting pitchers who should have received a call and didn’t. With a few extra breaks and some additional run support here and there, though, we might have ourselves a deeper debate. All-Star bologna aside, Lackey’s continued success and the Red Sox’ reliance on him speaks to how important he is both now and for the rest of this season. Ryan Dempster and Felix Doubront both deserve a lot of credit for their recent stretches as well, but Lackey’s performance has been exceptional. Sunday was a good barometer of his overall progress. Lackey essentially made two mistakes against the Angels, as the two runs he surrendered came on solo homers by Mike Trout and Hank Conger in the first and fifth innings, respectively. Other than that, he matched Weaver — a legitimate ace — pitch for pitch. It doesn’t mean that Lackey is worthy of the “ace” label, but he has definitely evolved into much more than just a viable back-of-the-rotation starter, and he seems to be getting better with each start.