Jon Lester has won his first three starts for Oakland, pitching like the game-changer the Athletics envisioned when they acquired him from Boston at the trade deadline. Oakland needs another strong performance from its new ace when it tries to avoid a sweep in Sunday night's series finale at the Atlanta Braves, as the Athletics - who held sole possession of first place in the American League West for 106 consecutive days - are now two percentage points behind the Los Angeles Angels. The Braves have held Oakland to five runs on nine hits in taking the first two games, and while six games behind first-place Washington in the National League East, they are much closer in the wild-card race.Atlanta sits 1 1/2 games behind San Francisco for the final NL playoff spot, winning three of its last four contests after dropping 11 of its previous 13. Justin Upton brings a seven-game hitting streak into the series finale while Chris Johnson, who went 3-for-4 with two RBIs in Saturday's 4-3 victory, is in the midst of a five-game run. The offense has contributed greatly to Oakland's skid, collecting five hits or fewer in four of its last six games while scoring fewer than four runs five times.TV: 8:05 p.m. ET, ESPN PITCHING MATCHUP: Athletics LH Jon Lester (13-7, 2.51 ERA) vs. Braves LH Mike Minor (4-8, 5.33)Lester has allowed six earned runs while registering 20 strikeouts over 21 2/3 innings in his first three starts for Oakland and is 7-0 with a 1.46 ERA in his last seven outings overall. He followed a three-hit shutout over Minnesota in his second turn for the Athletics with a performance against Kansas City on Tuesday in which he yielded three runs and hits over six frames. Lester beat the Braves on May 27 in Atlanta while with the Red Sox, allowing three runs and fanning seven in six innings.Minor seemed to benefit from being skipped in the rotation prior to his start against the Dodgers on Tuesday, as he allowed three runs with seven strikeouts despite losing for the third time in his last four outings. He is 2-4 in his last eight starts, yielding 34 earned runs on 64 hits (eight homers) in 44 2/3 innings. Minor has surrendered at least eight hits in each of his last five starts and five or more runs three times in that span.WALK-OFFS1. Oakland CF Coco Crisp is 0-for-8 in the series after entering the weekend 18-for-49 lifetime against Atlanta.2. Atlanta's offense has scored four or more runs in each of the last three games after producing four only once in its previous 13 contests.3. Oakland RHP Sonny Gray, who lost his fourth consecutive start Saturday, told reporters, "It's tough to go through this as a team, but I feel like everyone goes through it, and maybe this is our time right now."PREDICTION: Athletics 5, Braves 2