admitted that confidence is low at at the start of Ruben Amorim's reign ahead of Sunday's Premier League clash against Liverpool. United travelled to Anfield on the back of four consecutive defeats in all competitions, having not won away at their bitter rivals in eight years.
Amorim has endured the worst start of any Red Devils boss in over 90 years by losing six of his first 11 matches at the helm.
Another defeat on Merseyside would leave his side rotting in 14th, 14 points behind the Premier League's top four and just six above the relegation zone after 20 games.
Martinez has been one of Amorim's most trusted players since his arrival from Sporting in November, despite continued lacklustre performances since returning from injury last season.
The 26-year-old centre-back wore the captain's armband in the 2-0 loss to Newcastle United on Monday, while Bruno Fernandes served his one-match suspension for seeing red against Wolves.
And he was the member of the visitors' dressing room to briefly speak to the media ahead of the grudge clash at Anfield.
While Martinez conceded that United weren't in good shape mentally, he insisted that Amorim and what the Portuguese tactician was attempting to instil had his complete faith.
"I think in the first games [under Ruben Amorim], we played really well, and then our confidence, because of the results, when you start losing, the confidence is low," Martinez explained.
"It's normal, but we are working on details. For sure, when you lose, you see everything wrong, right?
"But I really trust in the manager, in the staff, in the team, and today, we have to take the step forward. We have to play and to show why we are here."
Martinez has started all 10 outings for which he's been available across the Premier League, Europa League and Carabao Cup since Amorim took charge.
His left-footed nature undoubtedly supports his case, given the 39-year-old head coach's persistence with a three-at-the-back formation.
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