Olivier Giroud scored his first Premier League goal of the season - and his first since April - as Chelsea beat Tottenham 2-1 to tighten their grip on fourth place.Marcos Alonso added a second for the Blues, who were made to sweat the final few minutes when Antonio Rudiger turned into his own net.Giroud's first Premier League goal since April arrived in the 16th minute when he drove his half-volley into the bottom corner after Ross Barkley's shot ricocheted off the post.Tottenham were disappointing in the first half and their best chance arrived in the 34th minute, but Lucas Moura's near-post shot was crucially blocked by Cesar Azpilicueta before, from the resultant corner, Willy Caballero tipped Davinson Sanchez's looping header over the bar.Marcos Alonso quickly extended Chelsea's lead at the restart with a low piledriver into the bottom right corner from the edge of the box.There was a moment of real controversy moments later as Giovani Lo Celso appeared to stamp on Azpilicueta, but it went unpunished with VAR deeming there to be no foul.Tammy Abraham's chance to score a point-blank tap-in was brilliantly saved by Hugo Lloris in the 78th minute before Alonso's free-kick crashed off the bar moments later.And the game took a tense turn for Chelsea in the final moments as a low ball from Erik Lamela looking for fellow substitute Dele Alli was deflected in by Rudiger.But Chelsea held on to maintain their top-four berth and now have a four point gap over fifth-placed Tottenham.