Aaron Boone reminded reporters on Sunday how the first half of last season ended: with an ugly walk-off loss in Houston that left the Yankees eight games back and in third place in the AL East. What a difference a year makes. After shaking off one of their few downturns of the first half, the Yankees closed it out with two lopsided wins over the Red Sox — using the familiar formula of sturdy starting pitching and a powerful offense — and entered the All-Star break atop the division and 13 games up on the Rays. How have they made such a stark turnaround? Let’s see how they did:

By now, Carpenter’s journey from two bad seasons in St. Louis to a minor league tryout with the Rangers to sudden Yankee star is well-known, but it’s no less stunning, as the lefty slugger has resuscitated his career and provided a ton of production — as well as another strong presence in the clubhouse — since his signing in late May.

The left-hander has shown that last year’s success was no fluke. He’s in Los Angeles at his first All-Star Game after posting a 2.63 ERA — the best in the rotation — over 17 starts. The challenge for Cortes and the Yankees will be keeping him healthy and effective as he blows past his career-high in innings pitched.

Holmes has been a revelation since being traded from the Pirates last July and is also in LA for his All-Star Game debut after emerging as one of the best closers in the league, making up for the faltering Aroldis Chapman.

Judge’s bet on himself is so far paying off, as he’s perhaps the leading candidate for AL MVP and could be primed for a run at Roger Maris’ American League— and franchise — record of 61 home runs, all while playing center field on a regular basis.

The left-handed rookie has appeared in just six games, but is among the pitchers who have provided much-needed depth and he’s allowed just three runs in 19 innings.

Trevino arrived in a trade from Texas during spring training and has exceeded all expectations, providing excellent defense behind the plate and more offense than he had earlier in his career.

Cole has mostly pitched like an ace, but he will be judged on how he does in the postseason — especially after last year’s dud in the wild-card game against the Red Sox in Boston.

King has pitched in a variety of roles out of the bullpen, allowed fewer base runners and struck out more hitters than in the past.

Another rookie reliever who has split time between The Bronx and Triple-A Scranton/Wilkes-Barre, Marincaccio tossed 15 ¹/₃ scoreless innings in his most recent stint with the Yankees until being sidelined by shoulder inflammation.

The left-hander who came to the Yankees in a trade last season has been even better this year, although he’s had a pair of bad performances that led to losses in Toronto and Boston.

After re-signing in the offseason, Rizzo has provided just what the Yankees had hoped, with lefty power and a steady presence at first base.

After looking like a perennial All-Star in his first two seasons, Torres slipped badly the past two years before a move back to second base and a return to form at the plate has made him a weapon once again.

LeMahieu is in the midst of a strong bounce-back season, both at the plate and in the field, where he’s provided valuable flexibility with strong play at first, second and third base.

The left-hander has taken another step forward and been a key part of what’s been an excellent rotation, cutting down on both hits and walks allowed.

Schmidt is currently at SWB, where he’s being used as a starter, since both he and others like Domingo German will likely be needed for rotational depth in the second half. Finally healthy, he’s shown why the Yankees selected him in the first round.

Severino had been effective and healthy for most of the first half and now the Yankees have their fingers crossed his lat strain doesn’t keep him out long.

Stanton has been especially reliant on the home run this season, as all but six of his 30 extra-base hits have been homers, but he’s been able to stay on the field and his ability to play some outfield has added flexibility to the roster.

Taillon looked to be on his way to the All-Star Game when he had a 2.30 ERA in his first 10 starts, but he struggled for much of the last month.

Gonzalez has been what the Yankees expected when they brought him in this spring, as the switch hitter has started games at four positions (shortstop, third base, left and right field).

Brought in as a potential stopgap for Oswald Peraza or Anthony Volpe, Kiner-Falefa has matched his typical output at the plate, and while he’s made too many miscues on routine plays, his defensive metrics at short aren’t bad.

Luetge became a trusted member of the bullpen a year ago, and while his command hasn’t been as good this season, he’s been mostly reliable.

Command has been an issue again for the right-hander who came to the Yankees from the Mets in exchange for lefty Joely Rodriguez this spring. Castro is out with a shoulder strain.

After an abysmal start to the season, Hicks has been better at the plate since June (.875 OPS), and while his defense in center has slipped badly, he’s been good in left field.

Donaldson has been just an average hitter this year, which isn’t what the Yankees had in mind when they picked him up — for $50 million over this season and next — and he caused one of the lone ripples in this smooth season with his Jackie Robinson comment to Tim Anderson of the White Sox, but he’s been solid at third.

While Trevino has been arguably the best defensive catcher in the majors, Higashioka is regarded in the middle of the pack or worse, and while he’s shown power at times in his career, he hasn’t shown much of anything this season.

Chapman is lucky the Yankees have been as good as they’ve been this year, since it’s overshadowed much of his ineffectiveness. The former closer is being hit harder than ever before and is walking a whopping 7.6 batters per nine innings. The Yankees are trying to get him to be effective in a different role.

The challenge for the right-hander was trying to replicate the dominance he had last season. So far, it hasn’t happened. Loaisiga has been both ineffective and dealt with right shoulder inflammation.

Gallo’s miserable tenure in The Bronx has been the biggest misfire in years for the front office, and his days with the Yankees figure to be numbered.

The lefty is coming back from last year’s elbow surgery and could return later in the second half.

The free agent-to-be was not as overpowering as he’d been in recent years before being shut down by Tommy John surgery.

After signing a new contract in the offseason, the manager has pressed nearly all the right buttons this first half.

The subject of much criticism during a mostly quiet offseason, when he sat out of the shortstop free-agent market and didn’t pick up another starting pitcher, Cashman looks pretty good in the final year of his contract. He’ll be put to the test again with the Aug. 2 trade deadline approaching.