AC Milan were indebted to another 18-year-old to keep in touch with the Champions League qualifying spots.
AC Milan were indebted to another 18-year-old hotshot to keep them in touch with the Champions League qualifying spots on Sunday while city rivals Inter maintained their iron grip at the top.
Teenager Alberto Paloschi came off the bench on 62 minutes for his Serie A debut and seconds later was celebrating his first senior goal from his first touch in the 1-0 win over Siena.
It was a confident finish on the half-volley from the edge of the area, keeping it low to find the net past Siena keeper Alex Manninger and Milan coach Carlo Ancelotti will now be looking forward to pairing Paloschi with his other 18-year-old sensation, the Brazilian Pato.
Before Paloschi's introduction the European and World Club champions looked far from impressive.
With Pato and Kaka absent, Ancelotti broke away from his usual 4-3-3 formation for 4-4-2 with Ronaldo and Filippo Inzaghi paired in attack.
It was a move that backfired badly with the World Cup and Champions League all-time leading scorers failing to gel and the midfield lacking inspiration.
Clarence Seedorf replaced Ronaldo at half-time and immediately made a difference introducing urgency and inspiration to the midfield and it was from his lofted ball over the Siena defence that Paloschi scored.
Siena will be disappointed that they didn't take at least a point from the San Siro.
With confidence high following last week's 3-0 win at home to Roma they had the better of the first half, with Mario Frick, Massimo Maccarone and Tomas Locatelli causing Paolo Maldini and Alessandro Nesta problems at the heart of Milan's defence.
The result means that Milan are now two points behind fourth-placed Fiorentina with 36 points, but have one game in hand.Champions Inter, meanwhile, maintained their eight-point lead with a relatively easy 2-0 win away to Catania.
It took the introduction of Honduran striker David Suazo to bring the game to life, with Mariano Izco's shot off the Inter bar the only incident of note in the first 60 minutes.
Argentina midfielder Esteban Cambiasso opened the scoring on 64 minutes when he poked in Javier Zanetti's header.
Suazo made the game safe two minutes later when he latched onto Zlatan Ibrahimovic's through ball to round goalkeeper Ciro Polito and double their lead.
Inter coach Roberto Mancini was relieved to have finished with three points and admitted that his team's lacklustre performance wasn't helped by the absence of some top players.
"We missed a lot of injured players and of course that was going to make life difficult," he said.
"We had to rest three or four very important players, players that needed a rest. We missed players like (Dejan) Stankovic and (Luis) Figo."
Juventus striker Vincenzo Iaquinta marked his first return to former club Udinese by scoring an important winner in a 2-1 victory.
The win means Juve are now four points above Fiorentina and can look ahead to trying to overhaul Roma in second place, who lead them by four.
It was not a convincing performance by Juve however, despite the return of goalkeeper Gianluigi Buffon following injury.
Buffon's rustiness was apparent when the home team opened the lead. He was unable to hold Fabio Quagliarella's near-post shot and he could only watch as the ball squirmed from his grasp to allow Andrea Dossena to poke home the rebound.
It was a poor first half from Juventus with Quagliarella and strike partner, Antonio di Natale causing the Juve defence all manner problems with their pace and movement.
The bianconeri improved in the second half and winger Mauro Camoranesi pulled them level on 60 minutes to signal and upturn in their performance.
With Nicola Negrottalie and Giorgio Chiellini stifling Quagliarella and Di Natale Juve took control with Iaquinta coming back to haunt his former employers by firing a low shot past Udinese goalkeeper Samir Handanovic for Juventus' third win in six games.