Martyn Rogers concedes that fatigue could be a factor in Saturday's trip to Totton.
The Yellows head to Hampshire following two gruelling FA Cup ties in quick succession against Bideford.
A 10-man Tivvy side produced a marvellous performance to hold them to a 0-0 draw at Ladysmead on Saturday, only to lose Tuesday's replay 1-0 at The Sports Ground.
Rogers, who was missing both Alex Faux and Adam Bilcock through injury for Tuesday's game, admitted that his side looked low on energy in the replay.
And with limited options available to him, he said it was imperative that his players were well-rested ahead of Saturday's encounter.
"I have said to them after the game on Tuesday that they need to rest up and replenish their bodies well to get ready for Saturday," said Rogers, who hopes to complete a new signing in time for the contest.
"We haven't got the biggest squad anyway so we can't change things around too much.
"The lads have put so much into the last three games. Every game for us is going to be difficult so we are going to have to work as hard as we can.
"I think Saturday's game took a lot out of the players. We were half a yard behind Bideford on Tuesday and not as sharp.
"I was very happy with how the lads finished off in the last 20 minutes, but we just did not have enough in the locker."
Bideford made a strong start to Tuesday's game, and they opened the scoring on just 11 minutes through skipper Richard Groves.
Dan Harrison then struck the bar with a header from inside the six-yard box, but Tivvy did offer a rally of sorts after bringing on both Khaled Badavi and Jamie Mudge.
Rogers also felt his side should have had a penalty after Josh Searle went down in the box but the referee disagreed, meaning it is the Robins who go on to visit Weymouth in the next round.
"It was a tight game. They probably started a little bit better than we did and got the goal. We did improve though," Rogers went on.
"I did think we should have had a penalty. Young Josh was taken down, but the referee said no.
"I think he read the report of the first game because he was so fussy it was unbelievable. He won't be on my Christmas card list.
"Over the two legs though, the lads gave me everything and I can't fault their commitment.
"There is a lot to build on in the last three games. We are disappointed to be out of the cup but lots of positives too."
In the first leg on Saturday, Owen Howe was dismissed after just eight minutes following an altercation with Matt Wright.
He then headbutted the former Tivvy striker as he left the field, although Wright was then sent off after the final whistle following an altercation with Jesse Howe.
Tivvy defended skillfully, and could have nicked it at the end with chances for Jesse Howe and Jimmy Hinds.
"Obviously, playing against your old team you always want to do well, but maybe I was too pumped for it," conceded Owen Howe afterwards.
"Matt Villis grabbed James (Richards) then grabbed me and chucked me to the floor. Matt Wright then squared up to me and said I headbutted him.
"The ref sent me off for a headbutt I never did, and it was then that I lost it. I've got a massive mark down my neck where Villis grabbed me. Everything kicked off and I just reacted to what happened basically."
Wright – still a fans' favourite at Ladysmead after his exploits last season – had a different take on the incident.
"All I was doing was trying to break things up and he has run up and headbutted me for no reason at all," he said.
"I don't know the boy – don't know him at all, never spoken to him before in my life. I don't even know who he is.
"Fair enough, you are playing against your old team, but if you want to prove a point, go and stick the ball in the back of the net, not by headbutting someone.
"Don't get me wrong, I appreciate the Tivvy crowd and the fans – they were unbelievable – but I think at the end of the day they can't be happy with what they have seen from a couple of their players."
