Fast forward to the 2019/20 season and Liverpool's side had been transformed.
Initially it was in attack where Klopp looked to put his stamp on the side.
Roberto Firmino, a 2015 summer signing from Hoffenheim, was deployed as a "false nine" and became a thorn in the side of defences who were bent out of shape by the Brazilian dropping deep to link up with the attackers swarming around him.
Sadio Mane arrived from Southampton the following season and was an instant hit.
The Senegalese scored an outstanding debut goal against Arsenal and continued to frighten defences thereafter with his pace and eye for goal. Mane claimed the Premier League Golden Boot in 2018/19 and scored 18 of his 90 PL goals in the Reds' title-winning season.
Mohamed Salah was the jewel in the crown of Klopp's attack. In his debut campaign in 2017/18, Salah broke the record for the most goals in a 38-match season, netting 32 times.
His combination of pace, skill and ability to cut in from the right flank reaped 19 goals in the title-clinching season.
In midfield, Jordan Henderson had perhaps his best season in 2019/20. He scored four goals and provided five assists, but offered so much more in terms of leadership, positioning and tackling ability.
His commanding influence on the team earned Henderson the Football Writers' Association Footballer of the Year award.
Fabinho was another rock in Liverpool's midfield, halting opposition attacks at source to protect the back four. He also had an eye for a long-range goal in 2019/20, scoring in matches against Crystal Palace, and crucially, Manchester City.
One of Klopp's first signings, Georginio Wijnaldum, was an understated presence in midfield. Tidy, tireless and positionally on-point, the Dutchman featured in all but one match in 2019/20, weighing in with four goals.
It was in defence, however, where Liverpool changed from contenders to champions.
After breaking into the first team in 2016/17, Trent Alexander-Arnold redefined the role of the right-back, producing a series of outstanding displays as Liverpool's chief playmaker.
In 2019/20 he laid on a remarkable 13 assists and scored four goals, numbers that earned him the Premier League's inaugural Young Player of the Season award.
On the opposite flank, Andrew Robertson was another menace going forward. Signed from Hull City in 2017, the Scotland captain proved an outstanding piece of scouting.
In the title-winning campaign, Robertson produced 12 assists, with only Alexander-Arnold (13) and Kevin De Bruyne (20) creating more.
In the heart of defence Virgil van Dijk, signed from Southampton in January 2018, was key to keeping out some of the best forwards in the division.
Powerful, quick, assured in possession and a superb reader of the game, the imperious Van Dijk was ever-present in 2019/20 as Liverpool strode to the Premier League crown.
Although he missed nine matches in 2019/20, Alisson proved invaluable as the last line of defence, producing brilliant saves when called upon. His excellence between the sticks helped Liverpool concede only 33 goals, the fewest in the Premier League.
Liverpool had travelled a long way from the team that lined up against Spurs in October 2015 to the side that ended a 30-year wait to become champions.