Sir Alex Ferguson has told Manchester United they cannot allow Manchester City to derail their title coronation "for a spell" as he backed Robin van Persie to recapture the prolific goalscoring form that announced his arrival at Old Trafford.
Van Persie scored 22 goals in his first 28 appearances for United but has struck only once in his past 12 outings for the club, with Monday's FA Cup defeat at Chelsea his ninth game without a goal for the league leaders since scoring the second against Everton on 10 February.
Ferguson suggested in a magazine interview this week that the "intensity" of United's season could be a factor in Van Persie's dip – though the striker did score three times in Holland's recent World Cup qualifying double-header against Estonia and Romania – but says he is unperturbed by the £24m forward's form.
"Robin doesn't need a rest, that's for sure," said the United manager. "He's a strong lad with a great physique. It's disappointing he wasn't awarded the goal at Sunderland [last Saturday, when Titus Bramble was adjudged to have scored an own goal]. I can understand that because it took a wicked deflection. His shot was fantastic. It was hit with such venom that it's not surprising it took a deflection. But his ability to manoeuvre his position at that point was excellent. The goals will come. All strikers have little dry spells – you always hope it ends quickly. It's just part of being a striker."
Ferguson's advice to Van Persie and all strikers suffering a barren spell, he revealed, was passed on to him by his father, Alexander. He added: "You have to get through that period and not lose your faith and belief in yourself. My dad always used to say make sure you batter the ball when you're in there, don't tap it or try and side-foot the ball in the net, batter it. That's what I always tell strikers – when you get in the position make sure you hit it.
"If the goalkeeper saves it, you can say what a great save. But if you try to side-foot it in and the keeper just catches it easily you'll get criticised for that. It's just being sensible and realistic. Robin's shot last week could have come off any defender because it was hit so well and that's the right thing to do."
United host City on Monday with a 15-point advantage over their neighbours, closest challengers and reigning champions. But with Arsenal and Chelsea also still to play this season, Ferguson says United cannot afford to be complacent with a 20th league title in sight.
"We've still got to win the title," he said. "We have eight games left. That's 24 points to play for. The way we've approached things is the correct way and that's to win the next game, that's what we've always tried to do.
"Hopefully it takes you to winning the league and then we talk about what the season has been like. It doesn't matter what people say outside of the club, it's about what we think inside the club about what we've achieved.
"The important thing is to win Monday's game. It'll be a big game for City. They'll want to come and derail us for a spell. I can understand their motivation – we'd probably have the same motivation. But we're at home. Our consistency in the league is there for all to see. I expect us to perform really well on Monday."
Wayne Rooney and Rafael da Silva are expected to be fit for Monday's derby having missed the Chelsea defeat, and the Sunderland win in Rooney's case, with groin injuries. The United manager confirmed: "Wayne and Rafa have started training this morning which is good news. Hopefully they'll be fine by Monday. Jonny Evans [hamstring] and Nemanja Vidic [back] are not there yet but hopefully they'll start maybe tomorrow or Saturday morning. We have a little bit of time on our hands to get most of the troops ready for the game."