Ajax manager Marco van Basten has warned his side they must win when he takes control of his first game at the Amsterdam ArenA against Roda JC on Sunday.

Van Basten saw his side concede a half-time advantage to lose their opening game 2-1 away to Willem II a fortnight ago.

That defeat was not the ideal way for the former Holland coach to begin his tenure at the club, especially after spending 30 million euros on new players during the summer.

And while Van Basten concedes it will take time for his new players to knit as a unit, especially given a number have been called away on Olympic and international duty since he took charge, he knows his side must bounce back immediately.

"We still have our doubts about some things," Van Basten said.

"We have only trained a few times with the whole group, so there is still a lot of work to do in the upcoming weeks, maybe months.

"But one thing is clear. We have to win on Sunday, because if we don't, we make it very hard for ourselves."

Van Basten may be forced to go into Sunday's game with Uruguay duo Bruno Silva and Luis Suarez after they only returned from international duty late on Friday.

Both players missed Friday's training session along with new signing Ismail Aissati who looks likely to be sidelined for two weeks after injuring a knee in training this week.

Spanish midfielder Gabri (ankle) and Robbert Schilder (knee) are also questionable starters while long-term absentees Jan-Arie van der Heiden and Mitchell Donald remain sidelined.

Roda coach Raymond Atteveld is wary of Ajax following their opening-day defeat.

"I expect an eager Ajax that will try to exert their will on us," he said.

"We are prepared for that. We must try to catch out Ajax and try to silence the crowd. That is the first part of the battle."

Roda recorded a 1-1 draw against FC Twente in their opening game of the season and Atteveld believes his side can also take something from their trip to Amsterdam.

"Against FC Twente we deserved the draw," he said.

"We played good football, the substitutions worked out perfectly and especially in the second half we fought like lions. That is what Ajax can expect from us tomorrow too."