The 28-year-old defender, whose existing contract was due to expire next summer, has penned a new five-year deal at the Stadio Olimpico.
The left-back joined Lazio from Dinamo Bucharest in 2008, and has made over 150 appearances for Stefano Pioli's side.
Radu, a Romanian international with 14 caps for his country, is Lazio's vice-captain, and helped the club to third-place finish in Serie A last season.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Napoli | 7 | 5 | 1 | 1 | 14 | 5 | 9 | 16 |
| 2 | Inter Milan | 7 | 4 | 2 | 1 | 16 | 9 | 7 | 14 |
| 3 | Udinese | 7 | 4 | 1 | 2 | 10 | 10 | 0 | 13 |
| 4 | Juventus | 6 | 3 | 3 | 0 | 9 | 0 | 9 | 12 |
| 5 | AC Milan | 6 | 3 | 2 | 1 | 14 | 7 | 7 | 11 |
| 6 | Torino | 7 | 3 | 2 | 2 | 12 | 11 | 1 | 11 |
| 7 | Atalanta BCAtalanta | 7 | 3 | 1 | 3 | 16 | 13 | 3 | 10 |
| 8 | Empoli | 6 | 2 | 4 | 0 | 5 | 2 | 3 | 10 |
| 9 | Lazio | 6 | 3 | 1 | 2 | 12 | 10 | 2 | 10 |
| 10 | Roma | 6 | 2 | 3 | 1 | 7 | 4 | 3 | 9 |
| 11 | Hellas VeronaHellas Verona | 7 | 3 | 0 | 4 | 12 | 12 | 0 | 9 |
| 12 | Como | 7 | 2 | 2 | 3 | 10 | 14 | -4 | 8 |
| 13 | Fiorentina | 6 | 1 | 4 | 1 | 7 | 7 | 0 | 7 |
| 14 | Bologna | 6 | 1 | 4 | 1 | 7 | 9 | -2 | 7 |
| 15 | Lecce | 7 | 1 | 2 | 4 | 3 | 12 | -9 | 5 |
| 16 | CagliariCagliari | 6 | 1 | 2 | 3 | 4 | 10 | -6 | 5 |
| 17 | Genoa | 7 | 1 | 2 | 4 | 5 | 15 | -10 | 5 |
| 18 | Parma | 6 | 1 | 2 | 3 | 10 | 12 | -2 | 5 |
| 19 | VeneziaVenezia | 7 | 1 | 1 | 5 | 5 | 12 | -7 | 4 |
| 20 | Monza | 6 | 0 | 3 | 3 | 4 | 8 | -4 | 3 |
| > Serie A Full Table | |||||||||
