West Ham launched a tentative £6million bid to lure the 34-year-old striker away from the Stadium of Light during last month's transfer window, but were swiftly rebuffed with the Black Cats knowing he represents their best chance of staving off the drop for a fifth successive season.
However, the last of Defoe's 12 goals to date this term came in a 3-1 home defeat by Stoke on January 14, and Moyes admits the former England international will need more chances if he is to continue to do what he does best.
The Scot said: "There was a bit of noise at the start of the window, but everybody knew that he was vital to us
But we have got to get him opportunities to score, and that's probably been something in recent weeks we have not done.
"We have not had enough opportunities
We had one or two in midweek that didn't fall to Jermain (in the 0-0 draw with Tottenham)
We made a couple of chances in the first half, but we need to try to get a situation where we are creating more chances.
"We miss Victor (Anichebe) for that as well because Victor brings other parts to the game and gets us a bit higher up the pitch at different times.
"But we have to keep getting Jermain those opportunities to score."
The knee injury Anichebe suffered during the 2-0 defeat at West Brom on January 21 is set to rule him out until April, and his misfortune prompted a late and ultimately unsuccessful transfer window flurry to sign a replacement with Sunderland seeing three bids for Leicester's Leonardo Ulloa rejected.
That move would have been funded in part by the proceeds of full-back Patrick van Aanholt's £14million departure for Crystal Palace - he could line up against his former club at Selhurst Park on Saturday - at the end of a difficult window during which funds were otherwise extremely limited.
Moyes will hope for better in the summer if he manages to keep the club in the top flight - they slipped back to the foot of the table in midweek and are now five points adrift of safety - but he has not yet even posed the question.
He said: "I've not asked
Look, we are only days over the transfer window, so I've not even thought about it.
"We are just getting on with it
We have got the group now, we have got to try to get focused on the games remaining
We are going to have to win a lot of the games we have got coming up, so that's the aim."
New signings Bryan Oviedo and Darron Gibson could be involved for the first time at Palace, where Moyes will go head to head with his immediate predecessor Sam Allardyce, who masterminded a remarkable rescue mission last term.
Moyes said: "He's been around the block, he knows exactly what's required
He has his own style, Sam, he's his own man and he's very experienced."
Source : PA
Source: PA