MONTE CARLO (MONACO), April 20: Boris Becker rallied from a set down to beat Jan Siemerink, 5-7, 6-3, 6-1, today to gain the second round of the Monte Carlo Open tennis tournament on Monday.Becker, a three-time finalist here and winner of six Grand Slams, is in semi-retirement this year and his rustiness showed making uncharacteristic errors on his serve in the first set.In other matches, French wild card Sebastien Grosjean defeated qualifier Nicolas Lapentti of Equador, 6-2, 6-4 and Magnus Norman of Sweden beat Marcelo Filippini of Uruguay, 2-6, 6-2, 7-6 (7-4). Also Wayne Ferreira of South Africa topped Sjeng Schalken of the Netherlands, 4-6, 6-2, 6-4. Schlaken took the place of Tommy Haas when Haas had to drop out because of a stomach ache.