(AFP) - Despite starkly contrasting playing philosophies, Liverpool manager Juergen Klopp and his Manchester United counterpart Louis van Gaal are grappling with similar problems ahead of their meeting at Anfield on Sunday.
While Klopp espouses hard-running, high-pressing, "heavy metal" football, van Gaal is all about patient ball retention, but both men are yet to find a consistent formula for scoring goals.
Liverpool's return of 22 goals from their first 20 league games this season was the worst in their history, while United have not scored so few goals at this stage of a season (27) since the 1992-93 campaign.
When the two teams do manage to make it happen up front, problems arise elsewhere.
Both sides scored three goals in midweek, but both also let three in at the other end - Liverpool at home to Arsenal on Wednesday, United away to Newcastle United the night before.
Liverpool at least had the satisfaction of a last-minute equaliser against Arsenal, Welsh midfielder Joe Allen slamming home a volley that left Klopp's men five points below the Champions League places in ninth place.
United are three points better off in sixth place, but they were on the wrong end of a 90th-minute goal at Newcastle, Paul Dummett equalising at the death after the visitors had led 2-0 and 3-2.
"It's about finding that balance so we're not giving away these sloppy goals just before half-time and just before the final whistle," said United centre-back Chris Smalling, echoing a theme picked up by captain Wayne Rooney.
"They're key times in the game and we need to make sure we're switched on."
United won 2-1 on their last trip to Anfield in March, which came in the middle of a six-game winning streak that suggested van Gaal had finally settled on a winning strategy after seven months of tinkering.
But United won only one of their last six league matches and 10 months on they continue to toil, having won only two of their last 11 games in all competitions.
One consolation for van Gaal is that he has yet to encounter the opprobrium that can greet a United manager after defeat by Liverpool, having triumphed in all of his three matches against them to date.
Indeed, United have a strong recent record in the rivalry, winning six of the last eight league encounters, and Smalling believes that his side will continue to enjoy the upper hand.
"I think in recent times we've done very well against them, obviously this year at Old Trafford and last season we've got very good results, so we're very confident of going there and causing them a problem," he said.
Klopp is up against United for the first time as Liverpool manager and he is relishing the occasion, describing showdowns between major rivals as "the salt in the soup".
The German has also been highlighting the importance of balance, but in his case he was referring to emotional factors.
Former Liverpool captain Steven Gerrard was sent off just 38 seconds after coming on in last season's equivalent fixture, for a crude stamp on Ander Herrera, and Klopp has urged his players to keep their heads.
"You can be over-motivated, that's possible," he told his pre-match press conference.
"You don't have to think too much about motivation in games like this because everybody knows about the importance.
"But the balance is always the most important thing. In football everything is about timing and the right thing in the right moment."
With Dejan Lovren and Martin Skrtel still sidelined by hamstring problems, Kolo Toure and Mamadou Sakho will continue in central defence for Liverpool.
Van Gaal has ruled out central midfield pair Bastian Schweinsteiger and Michael Carrick through injury.