Nuno Espirito Santo's Hammers took just two points from their first three games in the English second tier after their relegation from the Premier League last season.
But they have now won consecutive matches for the first time since January, scoring seven goals in wins against Wolves and Derby, to boost their promotion push.
Joel Piroe scored early at the London Stadium but the home side had to wait until late in the game before making the game safe with goals from substitutes Edvin Austbo and Mohamadou Kante.
"It took some time, being resilient, staying in the game and waiting for the right moments, but it's positive managing the game," Nuno told the BBC.
"And when we had space, we did well to kill the game."
Six teams are locked on 10 points, all of whom have played five games except Swansea, who are in action against Wrexham later on Saturday.
Will Lankshear's seventh goal in as many matches in all competitions gave Middlesbrough a 1-0 victory against previously unbeaten QPR.
The striker has impressed since his move from Tottenham in July and his predatory first-half finish at Loftus Road took Boro up to second in the Championship table.
Head coach Kim Hellberg hailed a "big" win.
"At the end, the game showed every side of what we can do," said Hellberg. "The first 65 minutes was brilliant. We had four massive chances to kill the game off.
"You always have the worry when you don't score but we defended very good, credit to the defenders."
West Brom and Bristol City are also on 10 points after wins on Saturday alongside QPR and Charlton, who both lost.