The Toffees slipped to 14th position on the Premier League table after suffering a 4-1 defeat to Liverpool in the Merseyside Derby on Wednesday.
Everton have now gone eight Premier League games without a win, suffering six defeats in that time.
Benitez’s rein started on a bright note but a loss of form and injuries to key players have contributed to a downward spiral.
The home fans made their feelings known to the club’s board throughout Wednesday’s game and pressure is building on Benitez, who became the first manager since 1894 to take charge of both Merseyside clubs in a derby.
The likes of Dominic Calvert-Lewin, Andre Gomes and Yerry Mina were absent for the defeat to the Reds and Moshiri is optimistic things will get better when Benitez gets to work with the full complement of the squad.
Moshiri told talkSPORT: "Football is about crisis one day and glory the following day. Rafa is a good manager and underperformance is largely due to the injuries.
"Next two weeks, we will get to a full squad and, in the meantime, results will improve. Rafa needs time to have his mark on the squad.
"He will be supported to add depth to the squad. Managers need time. I have no doubt that we will have a strong second-half to the season."