Premier League midseason awards: Chelsea top of class at half-time

We're halfway there. With 19 matches played (for most clubs), here's a look at the best, and worst, of the Premier League season so far.

Story of the Season: Back threes

Roberto Mancini once presided over an unfortunate experiment with back threes at Manchester City. It didn't achieve anything, except manage to confuse Joleon Lescott even more than his perpetual state.

Step forward Antonio Conte four years later, an Italian tactician who is similarly cosmopolitan to Mancini but has a knack of getting players to run through walls for him.

Since switching to a back three when 3-0 down to Arsenal at halftime on Sept. 24, Chelsea has scored 32 times, conceded four goals, and won a record-equalling 13 matches. Right now, every hiccup from Chelsea's title rivals is getting punished by the Blues.

Best Player: Diego Costa

Formerly a scapegoat from the Chelsea team that appeared to down tools under the watch of Jose Mourinho in 2015, and a player that apparently wanted to return to Atletico Madrid in the summer. Now, Diego Costa is providing performances of maturity and potency to fire the Blues to an early, strong advantage in the title race.

The nasty side of his game remains, but it's controlled. Last season, the Spaniard committed 1.6 fouls per 90 minutes, but has now cut those misdemeanours down to 0.9 in 2016-17. When it comes to getting fouled, he's increased his number from 1.9 to 2.8 per 90 minutes - a precious attribute for a striker that can contribute defensively.

Obviously forwards are judged on goals though, and his 14 goals in 18 appearances is the league's high.

Honourable mentions: Alexis Sanchez, Philippe Coutinho

Biggest Disappointment: Leicester City

Expecting Leicester City to storm to consecutive top spot finishes would've been fanciful - particularly after N'Golo Kante's departure to Chelsea - but the frail nature of its title defence has been distinctly unimpressive.

For large chunks of the campaign, the organisation of the back four has gone AWOL, the vision of the midfield's quickly dispatched long balls blinded, and the strikeforce has been simply limp. After abiding by the same starting XI for much of last season, Claudio Ranieri has no idea of what his best lineup is.

Leicester is languishing in 14th in the division, an uncomfortable six points above the drop.

Honourable mentions: West Ham United, Crystal Palace

Biggest Surprise: West Bromwich Albion

Tony Pulis was subject of unsavoury chants from the West Bromwich Albion support last term due to his insistence in fielding four centre-halves and players who aren't exactly blessed with attacking qualities. It wasn't an enthralling watch.

This season, however, the tracksuited gaffer has ditched his defensive mindset and embraced more forward-thinking players. Nacer Chadli, Matt Phillips, and Salomon Rondon have all shone at points in the first half of 2016-17, and the Welshman is even fielding an ambitious full-back in Allan Nyom and an emerging talent in Jonathan Leko.

Finally, the Hawthorns have a side comfortably situated in the top half that has the capacity to entertain.

Honourable mention: Victor Moses

Breakout Star: Jordan Pickford

Yes, Jordan Pickford has no choice but to be busy between the sticks for Sunderland, but if it wasn't for his heroics the Black Cats wouldn't be nearly clawing their way out of the bottom three right now.

The English youngster is elastic, throwing himself to the furthest corners of the onion bag to thwart countless frontlines this term. His outings against Tottenham Hotspur, Bournemouth, and Hull City were especially emphatic.

Unfortunately for manager David Moyes, Pickford followed a sizable throng of injured Sunderland players into the treatment room recently.

Honourable mention: Michael Keane

Best Signing: Joel Matip

It's no coincidence that Liverpool's two defeats have occurred when Joel Matip is absent from duty.

The best thing about the defender's arrival is that he cost nothing, and was even prepared to ditch Cameroon duty at the Africa Cup of Nations for his new club.

At long last, Liverpool could have bagged a centre-back as reliable as old Kop favourite Sami Hyypia.

Honourable mentions: Zlatan Ibrahimovic, Matt Phillips, N'Golo Kante

Biggest Bust: Simone Zaza

A quintessential panic buy.

West Ham clearly didn't send some scouts out to Italy or, indeed, to Euro 2016, as the under-fire brass drafted in Simone Zaza with days remaining of the summer transfer window.

The deal was a loan from Juventus, but with a mindbogglingly expensive obligation to buy for around €20 million. It looks like the Irons may have found a loophole to enable Zaza to return to Turin, but the initial €5-million cost in striking an agreement and the questions his goalless, squalid showings ask of West Ham's talent spotters lingers awkwardly over the London Stadium.

Honourable mentions: Claudio Bravo, Ryan Giggs' Swansea interview(s)

Favourite Moment: Swansea 5-4 Crystal Palace

Swansea City and Crystal Palace took the lead two times each, but in the end the latter was punished in a match of dreadful defending. November's cracker at the Liberty Stadium will be remembered for years to come, and its match-winner, Fernando Llorente, suddenly transformed himself from flop to first-choice forward in the tie. The meeting was also Bob Bradley's first win of two in his brief stay at the Swans' helm.

Honourable mention: Bournemouth's comeback vs. Liverpool

Best XI

David Silva edges ahead of his City teammate Kevin De Bruyne due to his remarkable consistency while picking up pockets of space through the middle. De Bruyne has been exceptional, but is still being shifted out wide on occasion as he learns the versatility Pep Guardiola insists upon from his most talented stars.