Signings have been made and new managers are now in charge at some clubs, but how much will actually change in the Premier League this season?

The two teams that finished at the top seem nigh-on impossible to shift, at least according to the statistical evidence compiled after an incredible 2018-19 title race.

Champion Manchester City and runner-up Liverpool lost five games between them as they battled for the trophy until the final day, leaving others trailing well behind.

Will the gap widen with Eden Hazard torn from Chelsea, or can Manchester United close in after laying stronger defensive foundations?

We assess those questions and more in the Opta data preview for 2019-20.

City, Liverpool set to dominate again

It will take something bordering on sorcery to prevent City and Liverpool from retaining their places in the top two.

The masterminds behind their success, Pep Guardiola and Jurgen Klopp, are the only current Premier League bosses to gain more than two points per game on average (2.42 for the former, 2.06 for the latter).

Klopp's competitive win percentage with Liverpool (57.2) even surpasses his level while in charge at Borussia Dortmund (56.4).

Moving to England has not been quite so successful in terms of victories for Guardiola, who won 75.2 percent of matches during his time at Bayern Munich. However, his City win rate (73 percent) still exceeds what he achieved with Barcelona (72.5 percent).

Consider also that both sides start games incredibly well — Sadio Mane and Mohamed Salah opened the scoring a combined 18 times last season, while Sergio Aguero did so on eight occasions — and it becomes tough to see who else is going to keep pace with them.

18 - The longest winning run in the Premier League stands at 18 straight victories, a record set by Pep Guardiola's Manchester City between August and December 2017. Juggernaut. pic.twitter.com/spStFBkbWP
— OptaJoe (@OptaJoe) July 22, 2019

Chelsea faces huge challenge to fill Hazard void

The acquisition of U.S. winger Christian Pulisic was a canny bit of planning on Chelsea's part, but there is simply no easy way to replace someone like Hazard.

Now at Real Madrid, the Belgium star left a lasting impression in his final season at Stamford Bridge, leading the Premier League in assists (15) and goal involvements (31) and finishing second in chances created (98, behind only James Maddison's tally of 100 for Leicester City). No other Chelsea player cracked the top 20 in any of those categories.

Hazard's 16 league goals accounted for more than a quarter of the Blues' total as a team and were directly worth 13 points, a figure only bettered by the 19 points which Pierre-Emerick Aubameyang earned for Arsenal.

Frank Lampard has no choice but to create a better balance of responsibility among the attackers he has in his squad at Stamford Bridge.

31 – Eden Hazard (16 goals, 15 assists) was directly involved in 31 Premier League goals in 2018-19, the most of any player in the competition last season. Swansong. pic.twitter.com/Ag3W74Htzq
— OptaJoe (@OptaJoe) June 6, 2019

Can Maguire, Wan-Bissaka fix United's porous defense?

How do you solve a problem like owning the leakiest defense among the teams that finished in the top nine of the Premier League? Throw money at it!

Well that is how Manchester United has approached the issue after splashing out over £100 million ($120 million) in the transfer window.

Their spending is understandable after conceding 54 goals in 2018-19, a record for the club in the Premier League and the most it has allowed in a league campaign since 1978-79 (63).

First to arrive was right-back Aaron Wan-Bissaka, who ranked second in the division for interceptions (84) and third in tackles (129) at Crystal Palace last term.

Then followed Harry Maguire, who became the world's most expensive defender when joining from Leicester City. The England international will go some distance to justifying that fee if United are to emulate the Foxes, who dropped only three points from winning positions.

Ole Gunnar Solskjaer has his own part to play; United led the way in terms of starting XI changes last season (131), which feels like a recipe for disaster.

78% - Harry Maguire won 78% of his aerial duels in the 2018-19 Premier League season; a better success rate than any of the 205 other players to be involved in 50+ aerials in the competition, just ahead of Virgil van Dijk (75%). Slab. pic.twitter.com/SK0OVlUHU6
— OptaJoe (@OptaJoe) August 2, 2019